Linear workflow and Gamma

I’ve had some requests for this tutorial in the past, but never came around to making it.
Fortunately Ismail Rebbane offered to write a guest post explaining this subject, so here goes :)

Linear Workflow and Gamma allow you to process texture, color and light in a correct mathematically way.
It has nothing to do with creativity or art, just a matter of working with correct math versus broken math.
We unfortunately can’t avoid it!

If you usually get dark corner, textures and color that doesn’t much the reference. or, doubling the light’s intensity all the time to make the scene brighter then, working in a linear manner is what you’re missing.

After you watch the video below, you’ll have a complete understanding of Linear workflow, Gamma and how to set it up correctly, starting from 3ds max, Vray and finally in Compositing (Photoshop, After effects, Nuke).

Quick tip:
One trick i learned recently from Austris to speed up the rendering process while keeping the Linear information, is to “change the color mapping to Reinhard with burn value at 0.8~0.9 and keep the mode set to none”.
You’ll get the same image and faster render time, because vray will sample the highlight areas more efficiently!

USEFUL LINKS AND RESOURCES MENTIONED

Color Mapping. Tone Mapping is very important, make sure to visit this page and learn more about it.
Gamma and LUT Preferences. Gamma policy in 3ds max.
ProEXR. Extracting passes with this tool is a piece of cake.

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About Ismail Rebbane
3D Artist and Visualizer, specializing in the field of Architecture Visualization.
Also the guy behind cgalter.com, which is the place where he shares what he learned over the years working in the visualization Industry.

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Color Correcting textures in 3Ds MAX

In this quick tutorial I want to show you how to easily make some basic adjustments to your textures directly in 3ds max, without going back to photoshop and making a new image file.

First, you have the Color Correction map. The name implies that it is the best tool for doing these adjustments. I find it a bit non-intuitive and clumsy for brightness/contrast adjustments, but it is great for shifting the hue or adjusting the saturation as well as desaturating your image completely. See the video to learn how it works!

Another great tool you can use is the Output map. It has a bunch of settings, but most of it’s power comes from the Color Map section. It works very similar to the curves in photoshop, but i think the way you can place the points and adjust curves is even better and more flexible.

Another quick and simple way to adjust a texture is by blending it with a color. You can either use a Mix map for a straightforward numerical blend, or Composite map to get access to different blending modes, masks and so on.

mix

comp

Using this sort of color correction in max, allows you to create whole shaders with color variations from a single bitmap. The great thing is – you get instant feedback on the material preview, so there’s no switching back and forth to photoshop, saving images, reloading textures and so on.
Here’s a quick example to give you some ideas (click to enlarge)!

colcorrect

UE4 – my first attempt at realtime archviz

A while ago there were some pretty cool arch viz videos floating around that were made in Unreal Engine 4. I looked at them and thought, “OK – looks nice, but it’s just an empty room with a bunch of chairs or some concrete walls that move slowly along with some piano music in the background”. At the time, I dismissed the idea as being something not worth the effort yet.

But then I got an itch.
What if the engine could handle somthing more like a real project? I just had to try it out myself :)
I spent some of my hard earned cash for a shiny new gtx980 video card, bought an UE4 subscription and started working my way through tutorials, forums, blogs, etc.
Obviously, I wanted to jump in the deep end and start with a somewhat complex project, something that could pass for a real arch viz job.

Here are my initial results. I think it’s pretty nice for a complete beginner!
Since a basic fps walk-around is boring if you’re not the one controlling the movements, I made a short animation (it even has some piano music) and a bunch screenshots.

Obviously there are some issues here and there, maybe the scene could use more accessories, etc. I also have to figure out the best AA method to keep away the jittering/jaggies in reflections and some edges. Overall I didn’t hold back and threw polygons and high quality shaders at the scene, just to see what the engine could handle with my gtx 980.

So here is my experience so far:

+ very nice physically-based shader system, I love the way it works. The node based system with some math/programming style functions is a-m-a-z-i-n-g
I can make a custom master material and adding things like fuzz, global distortions, scaling for all textures at the same time is a piece of cake!
+ making shaders is quick
+ the new 4.5 engine makes automatic lightmaps, so there’s no hassle with UV unwrapping anymore
+ the tutorials are pretty nice and help a lot with getting started
+ built-in cutscene editor (matinee) is fantastic. Very easy to set up multiple cameras, fading, slo-mo, etc. Everything can be animated as well.
+ great interactivity features (although I’m just starting to work with them, nothing to show yet)
+ it’s fun to walk around the scene you’ve created with all lights and shaders working in realtime

– sometimes crashes at the most unfortunate time (thankfully there is an autosave function)
– some weird animation glitches from time to time
– fbx import is ‘unfriendly’ (seriously, every object has it’s pivot reset to 0;0;0 ???)
– shaders lack some important features, the weak point at this moment is translucent/transparent objects with reflections
– you have to learn a whole new workflow if you are not used to game dev
– days go by too fast, I sit down at the computer in the morning, work a little bit on a scene, look up, and it’s already night outside :)

Overall, I definitely like the results and will be spending more time on developing my UE skills.

So is this the future? Will realtime game engines like UE, cryengine, unity, etc push the conventional methods off their throne?
Probably not. At least for high quality stills and high-end animation.
They will, however, most likely make up a new niche of realtime arch viz and quick, low budget animations.
The 1 minute animation I posted was rendered out in about 4 minutes at 2560×1440 resolution with quality bumped up all the way. Lower resolution and quality settings can be rendered realtime.
I’m guessing the workflow will become faster as I gain more experience (although it’s not that bad even now).

Now the only thing left is to convince the clients that they want or rather need this new fancy real-time interactivity. :)

Do you have any experience with realtime in UE4 or other engines? Please share in the comments – the good, bad and ugly!

My next test project will be an animated exterior scene. Not sure when I’ll find the time though, other ‘paid’ work takes priority at the moment.

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