Using Real World Map size with UV unwrapped models

Lately I’ve been using Real World Map sizes for my shaders. It’s just a more convenient way to reuse them on different models without adjusting the UVs.
The scale of textures always stays the same and you don’t need to worry about “Is it too small?”, “Is it too large?” As long as you get the scale correctly when creating the shader the first time, it’s going to be fine forever after.

If you are using this method for objects with regular mapping (box,sphere,planar,etc) it is very easy to just tick the little box that says real world map size in the UVW Map modifier and get a correct result. However, what if you need to use these shaders on a model that you have properly UVW Unwrapped?

There is an easy method to get the scale correctly, you just need to use a couple of little tricks:

So here’s my object, as you can see it is nicely unwrapped and works fine with regular map sizes.

regular_map

To get it working with real world map size, I’m going to add an UVW Xform modifier to it.
You can adjust the tiling in these little boxes.

uwvxform

But how do you know what numbers to enter so it matches the real world mapping?
Simple! Assign a map that has clearly visible borders (a simple grey square with black border works fine) and set the size to something like 10 cm (smaller for smaller objects and larger for larger ones). Now create a little box or a rectangle above your object with the same size as you set up for the map and from the top view adjust the tiling until it matches.

topview

In this case the magic number was 290

290

Now it works perfectly with any real world scaled texture!

fit

If you want to mix and match the UVs between realworld and unwrapped, just use a different UV channel like this.

channel2

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