CONFERENCE PURPOSE: MEET THE OTHER SIDE OF THE INTERFACE ENCOURAGE - PowerPoint PPT Presentation

CONFERENCE PURPOSE: MEET THE OTHER SIDE OF THE INTERFACE ENCOURAGE PEOPLE TO SPEND TIME IN R&D INTERACTION SHARE OUR EXPERIENCE

WHO WE ARE? - Small company in size. - Big company in ambitions. WHAT WE MAKE? - CG WORKS -DEVELOMPMENT ·3D Stills ·RT Apps ·3D Animation ·Plugins for 3D apps ·Lowpoly modeling ·RT Virtual walkthroughts ·2D Animation ·Plugins for 2D/video ·Video editting ·Scripting

ADVANTAGES: - Knowledge of both markets. - Complete custom pipeline. DISADVANTAGES: - Amount of time spent on it.

KEY POINTS IN R&D: Same philosophy you probably are applying in your company.

-Don’t think too big. THE REAL KEY IS JUST ONE IDEA -Don’t think too small. -You can’t create all you can imagine. -You can create things you have not imagined. -Don’t make the same as others. -Don’t reinvent the wheel. -Stay online and know everyday news. -Revisit the classics continously. -You don’t need to break the market. -Make a step everyday.

Almost all successful projects, even the ones that seems to appear from nothing, have lot of work and time behind.

TWO KIND OF PERCEPTIONS ABOUT YOUR WORK: You are a wizard and you make magic!!! (sometimes self-perception). The machine did it all, if you don’t do something is because you are lazy. Same as in CG Works!!! (Photoshop vs. libs).

WHAT DO YOU NEED? - Time. - Fresh ideas. - Logic. - Enthusiasm. - Technical skills.

CG MARKET SPECIFIC CONSIDERATIONS - Colors are just numbers in [0,1] range. - Prepare to R(80%) & D(20%). - There is still room to mimic real world and human perception. - There are great (unused) ideas in other disciplines.

OBJETIVES: Keep it as simple as possible.

OBJETIVES: Be the first one in the market.

OBJETIVES: Cover all the needs of the user.

LINEAR WORKFLOW: MUCH MORE THAN TWO CLICKS

What’s a linear function? f(x+y)=f(x)+f(y) & f(x*k)=f(x)*k VALID EXAMPLE! x--> 3 y-->4 f(x)--> x*2 f(x+y)= (x+y)*2 = (3+4)*2= 14 f(x)+f(y)=(x*2)+(y*2)=(3*2)+(4*2)= 14

What’s a linear function? f(x+y)=f(x)+f(y) & f(x*k)=f(x)*k NO VALID EXAMPLE! x--> 3 y-->4 f(x)--> x f(x+y)= (x+y) = (3+4) = 49 f(x)+f(y)=(x )+(y )=(3 )+(4 )= 25

We can aproximate light transport functions as linear operations. (trust me)

Old CRT’s don’t have linear responses in their conversion of voltages into brightness. Most common representation is a curve with 2.2 as a g n i r t a h t ? exponent. u o y o t l l e b

What this mean? If you translate directly your pixel intensity to voltage you’ll get a very dark image.

What’s the solution? Apply a transform function to all our graphic content called “Gamma Correction”. In a few words, since our screen makes all the images darker just put it brighter before sending them to the display.

TFT displays do not have this technology limitation. But all our images are non linear and the software was designed to use that non linear worflow, so TFT’s were built to mimic CRT’s response.

Steps in “Classic Workflow” - Read your textures and colors, remember that your files looks fine on your display, so they are gamma corrected. - Render and save the output file (you want to view it on your screen, so this is also gamma corected).

Hey! This looks fine but why I should change my workflow? - Your renderer works in a linear way but is assuming that his inputs are in a linear form, this not looks so much ugly since the nonlinear textures and the nonlinear display may cancel each other out to some degree. - Two wrongs don’t make a right.

What’s the linear workflow proposal? - Degamma your textures to make them linear. - Render using linear operations. - Apply gamma (again) to the final render.

Linear Workflow in two clicks...

Example.

Example 2

LINEAR WORKFLOW: STILL IMPORTANT AFTER RENDERING

Example: Adding lights (relight, multilight, layer blending...)

CAMERA RESPONSE CURVES STILL IMPORTANT AFTER RENDERING

What ‘camera response’ means? T he camera response function relates image irradiance at the image plane to the measured intensity values. Applications such as color constancy, photometric stereo, and shape from shading, require scene radiance rather than image intensity. T he camera response must be recovered in order to obtain image irradiance or ultimately scene radiance, from an image. http://www.cs.columbia.edu/CAVE/software/softlib/dorf.php

In few words camera response function quantifies the relationship between the input (real data) and the output (the capture made by the camera).

Usually they are expresed as curves. If we want to draw one image in our monitor we should use a exponential function that defines this curve: Irradiance=Intensity^2.2 n e e s u o y e v a H ? e r o f e b s i h t

How they measured that? LONG READ ABOUT HOW THEY GET DoRF AND EMoR TABLES TO TRANSFORM SCENE RADIANCE TO IMAGE BRIGHTNESS http://www1.cs.columbia.edu/CAVE/publications/pdfs/Grossberg_CVPR03.pdf How I could use them? YOU CAN USE IT AS TRANSFORM TABLES FROM A LINEAR INPUT IMAGE TO A TONEMAPPED OUTPUT IMAGE NOTICE THAT YOU SHOULD APPLY DIFFERENT A DIFFERENT TRANSFORM TABLE FOR EACH COLOR CHANNEL

Dealing with one pixel

Examples:

Let’s do some homemade R&D!!!

Step 1: create a gradient chart

Step 2: Print it.

Step 3: Get ‘color modulators’.

Step 4: Use them.

Step 5: some maths. Environment effects = Neutral photo - Digital gradient Digital sunglasses = sunglasses photo - Environment effects Sunglasses effects = Digital Sunglasses - Digital gradient Step 6: use the gradients as lookup tables

RESULTS.

Thomas Edison failed more than 1,000 times when trying to create the light bulb. When asked about it, Edison allegedly said, “I have not failed 1,000 times. I have successfully discovered 1,000 ways to NOT make a light bulb.”

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