Algorithms are eating us up

We’re all being pulled into big data’s sausage-making machine, finds Frank Swain

Dataclysm: Who we are when we think no one’s looking by Christian Rudder, Fourth Estate, £20

FOUR years ago I interviewed Sam Yagan, then CEO of OKCupid, about the mathematics underlying his free matchmaking site. Yagan explained

how they had cracked the love problem. The algorithms underlying his site couldn’t understand human emotion, but that didn’t matter. He simply had to chop people’s behaviour up into morsels a computer could digest: grist into a data mill.

I came away with the sense that something big was on the horizon: a time when machines could predict your idiosyncrasies without ever understanding them. Our shared future wouldn’t involve machines condensing into human-like androids, but great whirring server farms abstracting messy humans into clean mathematical patterns.

Dataclysm by Christian Rudder maps what that future might look like. Having co-founded OKCupid with Yagan and two friends, Rudder wrote the OKTrends blog to share the company’s quirky discoveries, from which camera makes you most attractive (Panasonic Micro) to the best chat-up line (“How’s it going?”).

When internet conglomerate IAC (owners of paid dating site Match.com) bought OKCupid in 2011, an OKTrends blog post detailing why you should never pay for online dating vanished

Algorithms know nothing of the heart, but they still cash in on it

overnight, and the blog ceased publishing.

Now Christian Rudder has returned, clutching a book packed with discoveries gleaned from the deluge of big data. Dataclysm is packed with the kinds of bon mots and revelations that made the OKTrends blog such a success.

The book is wider in scope, however: Rudder draws from big data sets – Google searches, Twitter updates, illicitly obtained Facebook data passed shiftily between researchers like bags of weed – to draw out subtle patterns in politics, sexuality, identity and behaviour that are only revealed

with distance and aggregation. The true aim of Rudder’s book

is not an examination of us, but of the data itself.

Given just a few metrics, commercial and governmental algorithms can prise open your private life and glean secrets never spoken aloud. From your history of purchases of everything from vitamins to handbags, for example, such algorithms can determine whether you are

“Machines can determine if you are breaking up with a partner, heading for bankruptcy – or pregnant”

breaking up with a partner, or heading for bankruptcy. They know when you are pregnant – and what your due date is. They are already used routinely to sell you things, and, of course, to sell you.

The book has a couple of understandable but important limitations. It is firmly focused on the US, so its conclusions may not be globally relevant. Then, as Rudder himself points out, he has to be careful not to draw too many grand inferences from his store

of impressive, but not gigantic, data sets. It should also be noted that while the book is punctuated by clean, compelling graphics, some of his trend lines buck

and sawtooth in ways that hint at big variances that go unacknowledged in the text.

It’s frustrating that Rudder spends so long examining differences between established groups of people, and less time using trends to identify hitherto hidden subcultures. It’s also frustrating that he often doesn’t pursue the questions he raises. For example, he documents how threatening mobs gather on Twitter, and how the search results of dating sites all too easily acquire a racist edge, but in neither case does he explore how measuring such patterns might help us combat them. (Maybe no one has really tried.)

Dataclysm will entertain those who want to know how machines see us. It also serves as a call to action, showing us how server farms running everything from home shopping to homeland security turn us into easily digested data products. Rudder’s message is clear: in this particular sausage factory, we are the pigs. n

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Request For Proposals Pruning and Hazardous Tree Removal on Public Grounds

The City of ______________ Request For Proposals Pruning and Hazardous Tree Removal on Public Grounds

Urban and Community Program

The goal of the program is to achieve a healthy sustainable forest and improve natural resource management within the community. The pruning and removal activities are the main focus of this Request for Proposals.

Tree pruning and hazardous tree removal will be specific only to those trees, on public property, in the designated areas of the tree inventory. ThE inventory is attached to this RFP. It should be understood for each firm’s proposal the project will begin with trees of highest priority and be considered in a descending order of priority. These trees are designated by the inventory.CONTRACT SPECIFICATIONS

The undersigned Contractor agrees to furnish to the City of______________, hereinafter referred to as “____”, tree pruning and removal services conforming to the attached specifications in accordance with the terms and conditions set forth.

SECTION 1 – GENERAL TERMS AND CONDITIONS – To provide all necessary transportation, supervision, labor, licenses, tools, equipment, services and expertise to apply to pruning and removal of evergreen and deciduous species as directed in this specification. It is required of the contractor to provide the necessary equipment and crews to complete the work in the specified period.

  1. Examination of Sites

Bidders shall inform themselves of all the conditions under which the work is to be performed concerning the site of the work, the obstacles, which may be encountered, and all other relevant matters concerning the work to be performed and the type of removals required under this contract.

The Contractor to whom a contract is awarded will not be allowed any extra compensation by reason of any such matters of concern which the Contractor did not inform himself prior to bidding. The successful Contractor must employ, so far as possible, such methods and means that will not cause any interruption of interference with any other contractor.

  1. Pre-Construction Meeting

Once the contract has been awarded and notice to proceed is issued, a pre-construction meeting will be held to review project specifications.

  1. Basis of Payment The contractor shall be paid for all the work upon completion as described herein. E. Starting and Completion Requirements

Work shall begin under the contract within two weeks of the date of notice to proceed. All contract work shall be completed by_______________or as agreed upon by both parties. The contractor shall not be entitled to any claims against the City for damages from any cause whatsoever in the progress of the work or any portion thereof.

The time for completion of the work may be extended upon written request from the contractor to the contract administrator, provided request is based on delays or suspensions that are not of the contractor; and such delays shall include, but not limited to acts or neglects of the City or others performing additional work, or to fires, floods, abnormal weather conditions; or the request is based upon a significant change in the scope of the work which has been approved by the State. The extension shall be the

equivalent number of working days or lost hours or in proportion to the amount of extra work compared to the amount of the original contract. Request for extensions in completion dates shall be made within twenty (20) days of occurrence. The contractor shall, at the time of submitting a request for extension, also submit supporting documentation justifying the request.

Time lost due to an inadequate work force, or failure of the contractor to properly supply or place orders for equipment or materials will not be justification for extensions of time.

  1. Inspection of Work

All work must be completed to the satisfaction of the City, or same will resolve his/her representative and any questions as to proper procedures or quality of workmanship.

  1. Damage to Property

Any damage to property as the result of the Contractor’s operations shall be the responsibility of the Contractor. Should the damage not be rectified within the time agreed upon or to the satisfaction of the _________, the City reserves the right to replace that which was damaged, or assess the Contractor such costs as any be reasonable and related to damage caused by the Contractor, and deduct these costs from any payment due the Contractor. The Contractor shall inform the _______ of any damage caused by the contractor’s operation on the day such damage occurs.

  1. Discontinuance of Work

The State shall have the authority to suspend the work, wholly or in part by written order for such period as the City may deem necessary due to conditions unfavorable to motorists, or due to failure on the part of the contractor to carry out orders given to comply with any provisions of the contract documents. The contractor upon receipt of either written or oral notice to discontinue such practice as determined by _____, shall immediately discontinue any practice obviously hazardous.

  1. Personnel and Equipment

The contractor shall supply all material, equipment and personnel necessary for the performance of this contract.

All equipment must be in compliance with bid specifications and all applicable federal, state and local rules and regulations.

All bidders must have in their possession or available to them by formal agreement at the time of bidding all necessary equipment, devices, tools, materials and supplies necessary to perform the work specified herein.

Bidders shall derive all or a majority of their income from arboriculture work. No day

labor or temporary part-time workers/employees shall be used in the performance of the contract. Only qualified permanent full-time/part-time employees trained and experienced in doing the required arboricultural work of this contract shall be used under this contract.

The contractor shall provide the necessary crews made up of a combination of equipment and personnel to complete contract specifications as specified in completion schedule.

Individuals found not to be following the intent of these specifications shall be removed from the work site at the request of the City.

  1. Certified Arborist

As a minimum, the crew supervisor(s) must be a current International Society of Arboriculture (ISA) Certified Arborist. Their names and certification number(s) must be included in the bid document to be considered for this project. Any change in the status of the “certified” individual(s) during the life of this contract must be reported to the City at the time of occurrence. All certification numbers will be verified through the ISA’s office. Failure to have a certified arborist on site at all times shall result in termination of the contract.

  1. Safety Standards
  2. All equipment to be used and all work to be performed must be in full compliance with the most current revision of the American National Standards Institute Standard Z-133.1-2000 and A300-1995, or as amended.
  3. Blocking of public streets shall not be permitted unless prior arrangements have been made with the Community Grant Contact or their representative. The Contractor is responsible to have vehicles moved during arboriculture work.
  4. The contractor shall provide adequate barricades, flag person(s), signs and/or warning devices during the performance of the Contract to protect the motorists and pedestrians. All placements of cones, signs and barricades must conform to the American Traffic Safety Standards. Yellow flashing lights mounted on a vehicle shall not be deemed as sufficient or adequate protection.
  5. Tree Location and Selection The project shall consist of the following four components:

Component One: Removal of Hazardous Trees indicated as Priority One Removal including the stumps of these trees Component Two: Pruning of Trees with a Priority One and Two Rating Component Three: Pruning of Trees with a Priority Large Tree Routine Prune Component Four: All other tree and stump removal and pruning recommendations

1.) Component One: Removal of Hazardous Trees Objective: To remove all hazardous trees as designated:

Priority One Tree Removal: Trees designated for removal, have defects that cannot be cost effectively or practically treated. The majority of the trees in this category has a large percentage of dead crowns and are potential safety hazards. Dead and dying trees that are high liability risks are included in this category. These trees are the first ones that should be removed along with the stump. (See Attachments)

2.) Component Two: Pruning of Trees with a Priority One and Two Rating Objective: To prune all trees that are hazardous to the community or are a potential safety hazard as designated:

Priority One Pruning: Trees recommended for pruning to remove hazardous deadwood, hangers or broken branches. These trees have broken or hanging limbs, hazardous deadwood and dead or diseased limbs greater than four (4) inches in diameter.

Priority Two Pruning: These trees have dead, dying, diseased or weakened branches between two and four inches in diameter and are potential safety hazards.

3.) Component Three: Pruning of Trees with a Large Tree Routine Rating Objective: To prune all trees that requires correction of structural problems that must be accessed by a bucket truck or manual climbing as designated:

Large Tree Routine Prune: These trees require arboriculture pruning to correct structural problems or growth patterns which would eventually obstruct traffic or interfere with utility wires or buildings. Trees in this category are large enough to require bucket tree access or manual climbing.

4.) Component Four: Pruning and Removal of Remaining Trees Identified on Inventory Objective: To prune and remove all trees as designated:

Small Tree Routine Prune: These trees require routine arboriculture pruning to correct structural problems or growth patterns which would eventually obstruct traffic or interfere with utility wires or buildings. These trees are small species, mature trees that can be evaluated and pruned from the ground.

Priority Two Tree Removal: Trees that should be removed but do not pose a liability to as great as the first priority.

Stump Removal: Remove stumps remaining from trees previously removed by the community.

Lists of trees to be pruned and removed are attached. L. Debris and Chip Disposal

Disposal of all logs, limbs, chips and debris generated by work described within this contract will be the responsibility of the contractor. Refer to Section 2 – Tree Pruning Specifications, Par A and B for specific disposal methods.

  1. Contact for Information

All questions should be directed to:

_____________________ _____________________ _____________________ _____________________ _____________________

  1. Deadline: Receipt of Proposals: October 1 (4:30pm), 2***

Proposal Submission:

All proposals must be submitted in an appropriately marked and sealed envelope to the above-mentioned address.

Four (4) copies of each proposal must be supplied.

SECTION 2 – TREE PRUNING SPECIFICATIONS A. Pruning and Disposal

  1. All pruning shall follow National Arborist Association Class II Pruning Standards for Shade Trees, an overview of which includes the following:
  2. To remove all dead, dying, diseased, interfering, objectionable, and weak branches.
  3. To remove under branches to permit clearance of approximately eight (8) feet on the sidewalk or pedestrian side of any tree.
  4. To remove all interior interfering branches, and one of all crossed or rubbing branches where practicable so the removal thereof will not have large holes in the general form of the tree.
  5. To remove one branch of all structurally weak “V” crotches occurring along the main trunk or developing within the tree crown, particularly in smaller trees. Special attention shall be given to the effect removal of such branches will have on the ultimate form of the tree.
  6. To remove trunk suckers and water sprouts especially where they are present below the bottom one half (1/2) of the tree.
  7. To improve the appearance of the trees trimmed.
  8. Attention is to be given to the eventual symmetrical appearance of the trees. Appropriate pruning shall be done in order to maintain a tree-like form typical of the species of the tree being trimmed.
  9. In lifting the bottom branches of trees for clearance, care should be given to the symmetrical appearance of the entire crown.
  10. All final cuts shall be made sufficiently close to the trunk or parent limb, without cutting into the branch collar or leaving a protruding stub, so that closure can readily begin under normal conditions. Excessively deep flush cuts that produce large wounds or weaken the tree at the cut shall not be made. Sharp pruning tools and saws shall be kept sharpened to result in final cuts with smooth wood surface and secure bark remaining intact. All trees six inches or less in diameter shall be pruned with hand and/or hydraulic pruning tool only.
  11. It is necessary to precut branches that are too heavy to handle to prevent splitting or peeling the bark. Where necessary, to prevent tree or property damage, branches shall be lowered to the ground by proper ropes or equipment.
  12. On trees known to be diseased, tools are to be disinfected with methyl alcohol at 70%

(denatured wood alcohol diluted appropriately with water) or bleach solution after each cut and between trees where there is known to be a danger of transmitting the disease on tools.

  1. Equipment that will damage the bark and cambium layer should not be used on or in the tree. For example, the use of climbing spurs is not an acceptable work practice for tree pruning operations on live trees.

The Contractor shall remove all tree limbs and tree debris from the sites and dispose of these limbs and debris in designated areas provided by the community in accordance with ordinances and regulations of the Community and the State of Arkansas. Those tree limbs and debris removed from the City grounds shall be disposed of in accordance with applicable ordinances and regulations of the City of ___________, ___________ County and the State of Arkansas.

The Contractor shall refrain from the practice of “free falling” the trees. All trees shall be limbed out prior to the final cutting of the trunk. Sidewalks, curbs, streets and manhole structures shall always be protected from the impact of falling wood by use of the tree or limb ground supports. Ropes or other mechanical devices shall be used to lower all limbs of sufficient size that may cause damage to other trees or surrounding public or private property.

Limbs and trunks temporarily placed in the boulevard areas shall be placed in such a manner as to eliminate any obstruction to motor vehicles and pedestrians. Brush and limbs overhanging a curb or pavement shall not be acceptable and under no circumstances shall these materials be allowed to lay on the boulevard or in the park overnight. The penalty for limbs and branches and logs left overnight shall be $100.00 per site per night.

All infectious diseased or parts of dead trees possible harboring vector of infectious diseases shall be removed from the City and shall become the Contactor’s responsibility to ensure destruction of the diseased or dead wood in accordance with the State statutes and local ordinances.

  1. Site Clean-Up

The Contractor shall clean up the site and remove and dispose of all debris at the end of each day’s operation. Site cleanup shall include removal of sawdust, small twigs, chips, leaves, trunks and limbs from the street, curb, parkway, sidewalk, private lawns and driveways with appropriate tools for the job. Aside from the stump left, the site shall be returned to the same state it existed in prior to the removal.

  1. Protection of Property

The Contractor shall take all necessary precautions to eliminate damage to adjacent trees and shrubs, lawns, curbs, walks, or other real or personal property. Holes made in the

lawn, regardless of size, shall be filled with sandy loam soil and seeded with a turf grass lawn seed mix. Vegetation surrounding a tree marked for removal/pruning shall be disturbed as little as possible.

  1. Protection of Overhead Utilities

Removal/pruning operations may be conducted in areas where overhead electric, telephone, and cable television facilities exist. The Contractor shall protect all utilities from damage, shall immediately contact the appropriate utility if damage should occur, and shall be responsible for all claims for damage due to his operation. The Contractor shall make arrangement with the utility for removal of all necessary limbs, and branches that may conflict with or create a hazard in conducting the operations of this contract. If the contractor has properly contacted the utility in sufficient time to arrange for the required work by the utility, delays encountered by the Contractor in waiting for the utility to complete its work shall not be the responsibility of the Contractor.

  1. Additional Information Each bidder shall be asked to proved the following data with their bid:
  2. A statement of the items of equipment which the bidder proposes to use on the project, together with a statement noting which of these items of equipment the bidder owns, and separately, those items which are leased to the company.
  3. Equipment List – Include manufacturer and model A. ___________________________________________________________________ B. ___________________________________________________________________ C. ___________________________________________________________________ D. ___________________________________________________________________ E. ___________________________________________________________________ F. ___________________________________________________________________ G. ___________________________________________________________________ H. ___________________________________________________________________ I. ___________________________________________________________________ J. ___________________________________________________________________
  4. Name, employment status and number of personnel who would be used to do designated tree work for the City.

Person ISA Cert.#,CDL,etc.  Employment Status     Year/Months Employed

________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

  1. At lease three (3) Commercial references who can attest to the contractor’s ability to fulfill this contract. Include names, addresses and phone numbers.
  2. ContactName: Organization:

Address:

Phone:

  1. Contact Name: Organization:

Address:

Phone:

  1. Contact Name: Organization:

Address:

Phone:

____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________

____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________

____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________

Any bidder may be required by the State to submit additional data in support of the bidder’s claim to be competent to carry out the terms and provisions of the contract.

SECTION 3 – BID SHEET

The undersigned hereby affirms and states that he prices quoted herein constitute the total cost to the State for all work involved in the respective items and that this cost also includes all insurance, royalties, transportation charges, use of all tools and equipment, supervision, overhead expense, inspection costs, all profits and all other work, services and conditions necessarily involved in the work to be done in accordance with the

requirements of the Contract Documents considered severally and collectively.

The undersigned contractor offers to provide the City of ____________, Tree Pruning and Removal services conforming to the specifications and in accordance with the terms and conditions herein specified.

City of ______________ Tree Pruning and Removal

Site

Project Total

SUPPLIER:

ATTEST:

ATTEST:

Component

One Two Three Four (prune) (removals) (stumps)

# of Trees

_______ _______ _______ _______ _______ _______

_______

Unit Price

_______ _______ _______ _______ _______ _______

Total

_______ _______ _______ _______ _______ _______

_______

__________________________________________ (Company Name)

___________________________________________ (Street)

___________________________________________ (City)      County Postcode ___________________________________________

(Contact Person and Phone/Fax Numbers)

________________________ Submitted by: (Signature)

________________________ (Title)

________________________ (Signature)

________________________ (Title)

_____________ (Date)

_____________ (Print Name)

City of ___________________ By: ______________________

(Name) __________________________

(Date)

THIS BID, WHEN ACCEPTED AND SIGNED BY AN AUTHORIZED SIGNATORY OF THE CITY OF_____________, SHALL BECOME A CONTRACT BINDING UPON BOTH THE PERSON, PARTNERSHIP OR CORPORATION, TO SUPPLY OR PERFORM AS SPECIFIED AND UPON THE LOCAL COUNCIL TO ACCEPT THE PRODUCT OR SERVICE.

Final Project; Some Rendering With mr Daylight & Eyes

Eyes are an important, if not the most important factor in creating a life like model of a human head. A full day was set aside for investigating the best methods for creating them. This YouTube video below is one of three excellent tutorials with clear visuals,  clear audio and easy to follow methodology for creating a human eye.

Fig.1. One of several iris textures available on seekanddestroygame.com.

All the textures used for making the eye where found on the corresponding website http://www.seekanddestroygames.com/goodies. along with a couple of custom brushes for PhotoShop (PS). For example; vein brush, which produces a good variety of vein structures.

Fig.2. Sclera from a real human eye.

Fig.3. Finished texture completed in PS.

Fig.4. Eye rendered in mental ray.

The above eye has had a Morpher modifier added so it can dilate. This is controlled by  manipulators for ease of use. Dilation may be shown in the final video of the renders.

Fig.5. Iris dilated.

Fig.6. Iris open.

Fig.7.

Fig.8.

Fig.9.

Figures 7,8 and 9 are the first renders with the eyes  and mr Daylight added.

This is as far as it goes with mental ray for the time. Rendering with Vray and Scanline will follow in the next blog

Final Project Subsurface Scattering (SSS) mental ray

Rendering Skin With Mental ray.

In 3dsmax the default render option is Scanline. To change this to mental ray; go to the Render Setup > Assign Renderer > Choose Renderer > mental ray.

There are four Subsurface Scattering materials within mental ray: –

  1. SSS Fast material
  2. SSS Fast Skin material
  3. SSS Fast Skin material plus Displacement
  4. SSS Physical material

The first three are described as non-physical shaders and the fourth described as physical.(Livny, 2008 pp633-678) This last shader is used for single layered material such as jade, milk, soap, wax etc. and calculates accurate renders of these materials. Physical shaders are difficult to set up and are not used for skin rendering. (Livny,2008 pp679)

The first three however are used for multi-layered materials such as skin, where physical accuracy is not required (van der Steen 2007 pp176-177) The parameters are set out in an easy to use roll-out, with all the layers listed together for manipulating. (Figure. 1 .) The user can adjust the parameters to suit the overall outcome of the final render and need not be tied to realistic computations and so has a larger scope for creativity.

Fig. 1.

SSS Fast skin will be used as the shader from mental ray, to render the subject, as it is the basic shader that mental ray uses during the process of creating skin .  Using SSS Fast Skin plus Displacement removes some of the controls from the user, adding displacement by default. A displacement map can be added later if needed, while SSS Fast material on its own does not give parameters for epidermal and sub-dermal scattering, two important factors in skin rendering.

SSS shaders use real world units to scatter light. There is a Scale Conversion Factor in the SSS Fast Skin rollout. If the model is to small, when the SSS Fast Skin is applied, then light will scatter through it too much giving it a plastic appearance. (Figure.2.) If the scale is too large then the scattering will not visually affect the model and give it a stone or clay appearance. (Figure.3.)

Fig.2. Here the Scale Conversion Factor is set at 0.1.

Fig.3. Here the Scale Conversion Factor is set at 2.

Fig.4.  Here the Scale Conversion Factor is set at 1.

In Figure.4, the Scale Conversion Factor is set at 1by default. In this case, this setting appears to be correct judging by observations of backscattered light penetrating through the right ear.

When an inverted gray-scale map (Figure.5.) is added to the bump shader (Figure.6) and the Specular weight is reduced from default 0.3 to 0 the

Fig.5.

.

Fig.6

Fig.7.  Specular Weight #1 set to 0. and bump map set at 0.05

.

Fig.8. Overall Specular Weight set at 0.4

Fig.9. Lighting from both sides and rear.

Fig.10. Back of subjects head.

That Seam is still there!!! GDI!

Fig.11. The individual maps used in the creation process.

Final Project: Subsurface scattering (SSS)

Basic overview

The performance of current Graphic Processing Units along with advanced 3d and 4d scanners, study of light propagation via subsurface scattering and in-depth analysis of physical skin composition, has made it possible to render realistic 3d images of human skin. Fig.1 is an example of this.

Skin has always been difficult to render (Eugene d’Eon & David Luebke. 2007) Human observers have a keen sensitivity to the appearance of skin and will be aware of subtle characteristics such as pores, wrinkles, freckles and scars, etc. especially on a human face.  If these characteristics are absent, the observer will notice quite quickly. It is important, therefore, when creating a believable, realistic human model in 3d, to include these features.  Thankfully 3d/4d-scanning technology allows this level of detail to be captured. However, surface anomalies alone will not create realistic skin. Another difficulty and one, which is vital, is achieving the translucency ascribed to skin.

Translucency lets light penetrate beneath the skins surface, scatter, get partially absorbed and then exit from a different point from where it entered. This process is sometimes called ‘Subsurface Scattering’ or ‘SSS’ and is simulated using algorithms in popular 3d rendering engines.

Fig.1

Light.

“The perception and interpretation of light is greatly influenced by the different viewing devices, whether a human eye or a camera’s film or digital sensor. Light perception and behaviour considerations are at the forefront of photorealistic imaging. To render a realistic image, you must mimic the natural behaviour of light and it’s interaction with surfaces, as well as understand how it’s perceived by recording devices, be they digital or film stock.”(Mentalray A3d artists guide Pge 284.

Subsurface Scattering (SSS)

When light penetrates and scatters within a surface, it’s characteristics may be described as subsurface scattering (SSS). Examples of materials that correlate to this effect are milk, jade, wax, fruit snow, skin etc.

SSS methods come from work by Henrik Wann Jensen and colleagues, which started in the late 1990’s where he introduced a model for subsurface light transport in translucent materials.

His work stems from previous research on bidirectional reflectance distribution function (BRDF) (Nicodemus 1977).

The BRDF model describes the transport of light, entering a material and exiting at the same position. It is a very simple approximation and may be used for materials such as metals but is insufficient for translucent materials, which scatters light significantly beneath the surface. BRDF creates a hard artificial appearance, as it does not blend surface features such as geometry and material colour and is mostly focused on surface scattering.

Bidirectional surface scattering distribution function (BSSRDF) on the other hand, is a more detailed model of light transport through a translucent material. It permits proficient effects simulation such as colour bleeding within a material and diffusion of light into shadowed areas.

Both BRDF and BSSRDF are defined by mathematical equations that analytically compute the movement of light as it moves through an object. The latter takes into account subsurface diffusion in anisotropic surfaces.

http://graphics.ucsd.edu/~henrik/papers/bssrdf/bssrdf.pdf

Skin

There are three main parts to human skin: Epidermis; sub-dermis; and sub-cutaneous. The epidermis is the outer layer, which is semi-translucent. There are no blood vessels within this layer. It filters out most of the blue wavelengths and some red. More of the shortwave green and blue is lost at a deeper level. Only the long wavelength (red) can go deeper to the sub-dermis where the blood vessels are and, at some points on the human body, all the way through, such as the ears or between digits.

The next blog will have examples from the subject model where SSS has been applied.

Final Project: Textured Map results

There were several attempts at getting the UVW unwrap textured, using the photographs taken early in the project. (photo-shoot)

In 3dsmax there is a method of rendering out the textures as UVW maps that will fit exactly over the UVW mesh. It is called ‘Render to Texture’

Fig.1 UVW unwrapped Mesh.

Fig.2 Baking out a texture map.

The rendered texture is visible in the render window when the photograph is baked out as a UVW map. It was then incorrectly saved from the window to TGA file format for blending in photshop. The problem was that the image in the render window contains all the shadows from the default lighting in 3dsmax, leaving it virtually useless as a texture for the model.

The ‘Render to Texture’ modifier actually saves the baked images out automatically, without the shadows caused by default lighting. Only the shadows created in the original photo-shoot will be present, that is why it is extremely important to photograph the subject in good lighting conditions, producing  flat, shadow free results.

Fig.3 The dark shadows under the chin are from the default lighting in 3dsmax

Comparisons between the ‘automatic rendered file’ Fig.4 and the ‘saved from render window file’ Fig.5

Fig.4

Fig.5

Fig.6 shows the back of the subject head. An unwanted seam is visible but will hopefully be removed by creating a procedural map for texturing

Fig.6

There was an issue concerning image size and whether the texture should be baked at 1024 x 1024, 2048 x 2048 or 4096 x 4096.

4096 would show much more detail and would be ideal if the final model was going to be viewed really closely but this would greatly slow render time, especially when a subsurface scattering shader was added. Rendered at 2048, would still show ample detail but close-ups would have to be avoided. The render time will be much quicker. Fig.7 and 8 show the differences between detail at 2K and 4K.

Fig.7

Fig.8

The next step in this project is SSS or Subsurface Scattering.

Final Project; UVW Unwrap & Projection Mapping.


Before unwrapping the model some rough edges needed cleaning up.

The base of the neck had deformed polygons due to the subject moving their head during the 4D scan. The retopologized head is exported from MudBox into 3dsmax for the clean-up process.

The model now has a much lower poly-count compared to the original. All of the UV work will be carried out at this low level, which will enhance the speed of the working process.

Converting to an editable poly, selecting the offending vertices and dragging them into a reasonable symmetry in relation to the rest of the model required careful consideration so as to keep with the contours of the subject as viewed from the photo-shoot: – http://jamesmcsparron.creativetechnologies.info/2013/02/27/430/

Fig.1

Unwrapping the model in the least possible pieces will make it easier to map, rather than unwrapping several smaller parts and then attempting to connect them together.  Fig.1 shows the green lines where the model was seamed for unwrapping.

Fig.2

This can be carried out quiet easily in 3dsmax, where the area to be sliced can be defined using the edge selection and then converted into a seam using the ‘Convert Edge Selection To Seam’ toggle. Selecting ‘Quick Peel’ unwraps the model and flattens it ready for mapping. Fig.2

The UV coordinates are a fundamental part of the model, so as a final check for mapping smoothness a checker material is applied. Fig.3 It is important to get this as perfect as possible before continuing.

Fig.3

There is an inevitable seam line but this can be hidden at the back of the head and may be hidden by hair or a hat.

The next step is to project the photographs from the photo-shoot, onto the model.

The photograph is projected back onto the model with the same camera optics that they were taken with. There are two techniques used to do this.

The first method, and one which in this case will be avoided, is flat(planar) mapping. This method leads to a large number of errors, for example, the whole front of the face being incorrectly enlarged, causing stretching out and down the side of the head. There is a lot of correcting needed to be carried out, in Photoshop, to fix these problems.

The other method is projection mapping (camera mapping). This method has little to no distortion when projecting the photographs onto the 3D model.

Fig.4 is the first attempt at camera projecting onto the model. This is only one of fourteen photographs taken of the subject. It will be baked to the model before the rest of the images are projected.

Fig.4

After all the increments are projected, the UVW is taken into Photoshop to blend any obvious seams.

FInal Project ‘A Brief Summary’

Comparisons of 3D Render Applications used in the Creation of Human Skin Synthesis.

As the title pronounces, this project has set out to compare the various render engines used with 3D software (3dsmax) to discover how each are applied to the creation of realistic human skin.

Initially there was going to be a deliberation of at least five different rendering applications but now that number is down to three. The reason for this is to make sure that comparisons are fully carried out and so fulfilling the original proposal.

If however there is time remaining in the project, other rendering applications can be considered and compared.

The three apps are, Scanline, mentalray and Vray, with Maxwell and Final Render to be considered after.

The human head has a variety of skin textures, colours, transparencies and thickness’s, therefore proves a good paradigm for testing each render engine.

There was some apprehension to building a human head from scratch. It would have to be very well modeled, to be rendered believably. Fortunately there are scanners available that capture very detailed representations of a given subject and can produce an excellent 3D mesh from the results.

Access to a 4D scanner at the University of Ulster Coleraine campus, over seen by Professor Philip Morrow and his PhD student Keith, was given with much appreciation.

The 3D mesh may not be used directly as it is rather dense, made up of a few hundred thousand polygons, or in this case, triangles. There are no map coordinates in the scanned data to allow artists to paint or texture the model.

Features cannot be added or removed by digital sculpting because of this same reason and the triangles do not flow with the muscle contours of the face. Therefore the model needs to be cleaned up and the polygon count reduced in order for it to be used by an artist with minimal processing, in other words, retopologized.

Re-topology is like adding a new skin to the old misshapen existing skin.

There are re-topology software tools that may be used to quicken this process.

It may be carried out directly in 3dsmax or by sculpting software such as zBrush or Autodesk MudBox but the most recommended software was Topogun, which produced results quickly and efficiently.

The re-topologized head may be imported into 3dsmax to create realistic skin features.

The model will be UVW unwrapped in 3dsmax and several maps created to replace the details that disappeared from re-topology. The epidermis and sub-dermis may be created using a copy the UVW unwrap and veins; freckles and other characteristics may be produced with a similar copy.

Prior to using the 4D camera system a photo-shoot was carried out of the chosen subject http://jamesmcsparron.creativetechnologies.info/2013/02/25/final-project-photo-shoot/

It is hoped to use these images to create the UVW maps for rendering. They have a better resolution than the ‘BMP’ files that came from the 4D camera data.

The subject was sitting on a swivel chair, when the images were captured so the chair could be moved through the increment of 360° rather than the subject twisting his neck. It is regretted that a swivel chair was not used similarly for the 4D scan, during which the subject moved his head from left to right, to capture the different angles, while keeping his shoulders still. This forced the neck muscles to contract and stretch, creating some discrepancies in the ‘obj’ files in the neck area. It is hoped that when a displacement map is added to the adjusted neck polygons, the issue will be fixed.

It seems that a large percentage of this project, so far, has been on creating a human head for rendering instead of focusing on the rendering applications themselves but constructing the test block is a very important part of the process and requires much attention to get right if the skin synthesis is to work to it’s best.

If the test block is modeled correctly from the onset, the rest will hopefully fall into place with very little problems.

The blog entries in CTnet are mostly images with some text to describe them.

It is images that best describe the re-topology process.

At the first proposal meeting at the conference room, in the MH building, it was believed that this project should be 60% theory and 40% practical but at this time it is appropriate to reverse this to 40% theory and 60% practical as there seems to be more time spent dealing with practical issues.

When finally the test bock is rendered with the said render engines, the final renders will be sent to a selection of professionals who work in the 3D industry for analysis. The process may also be posted in several 3D websites such as ‘Polycount wiki’, ‘3D printer hub’ and CG Society in order to receive user feedback.

Final Project 4DSCS Coleraine Campus

4D Stereo Camera System.

The system employs three 50mm video cameras mounted on a vertical axis 110mm apart. The top and bottom cameras captures the subject as grayscale while the middle captures colour data at 25fps.

The lens are Fujinon CF50HA-1 high resolution design, providing support for up to 1.5 megapixel camera resolution and low distortion design for accurate image reproduction.

Two linked computers with a software package consisting of a number of modules namely diVideoCapture, DI3D, diView4, DI4Dtracker.

The camera system captures a sequence of ‘obj’ images over time.

The subject moves their head, slowly, from left to right or tilt from backward to forward to capture surface detail from all angles. A back profile may be recorded to receive a full 360° perspective of the subject.

LIghting fixture uses 55Watt compact 5500K (Daylight) and 3200K (Tungsten) lamps and are Kino Flo Diva Lite 400 series.

Callibration plate for setting the cameras before recording.

The results of the scans were sent via the Cloud drive ‘SugarSync’ and for each of the following there were separate ‘obj’, ‘mtl’ and ‘bmp’ files.
.
Look Up            – George_002_010
Look Down      – George_002_318
Front                  – George_001_270
Back                    – George_003_040
Left                     – George_001_042
Right                   – George_001_545
3/4 Left              – George_001_150
3/4 Right            – George_001_375
Back Left            – George_004_021 (Noisy)
Back Right          – George_004_511
3/4 Back Left     – George_004_111 (Noisy)
3/4 Back Right   – George_004_470



Above are the separate increments of the subject, imported into 3dsmax,  to create one full 360° representation from all the pieces before re-topologizing. ( the centre image has had  it’s ‘bmp’ file imposed onto it. This helps define the lines of the eyes, mouth, nose and ears.)


The different colours makes it easier to join the segments together rather than the original grayscale.
When the ‘bmp’ files are dragged directly  into 3dsmax they fit straight on to their ‘obj’ counter part.
This is experimental at this point. The images from the photo-shoot will probably be used, rather than the ‘bmp’ files)
The Image below was copied from  http://www.foundation3d.com/forums/showpost.php?p=76417  to be used as a guide for retopologizing the subjects head in ‘Topogun’.
Re-topology, using ‘Topogun’ was fairly straightforward but the software crashed quite often and even though the file was saved, it would re-open with most of the detail missing and the topology would have to begin from scratch.
The above image is from ‘MudBox’, which is a very fast way to carry out re-topology, but the polygons on the base head on the right need to be greatly altered to have them flowing the way they are needed for a particular subjects head otherwise it can end up looking like the image below.

However, when the re-topologized head was taken from ‘Topogun’ and imported into ‘MudBox’ the result was a low polygon representation of the Subjects head which may now be used as a base for a displacement map.
Reference

YouTube. 2013. Retopologize scan data in Mudbox 2012 – YouTube. [ONLINE] Available at:http://www.youtube.com/watch?v=qKTUIsPQ_uM. [Accessed 05 March 2013].

Foundation 3D Forums – View Single Post – SubPatch Modeling Tutorial (Nudity Warning). [ONLINE] Available at:http://www.foundation3d.com/forums/showpost.php?p=76417. [Accessed 13 March 2013].
Mini-Topogun Tutorial on Vimeo. [ONLINE] Available at: https://vimeo.com/21336102. [Accessed 13 March 2013].