1. #1
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    Lightbulb Tutorial: Creating Reflection (and other) Maps for Export

    As you probably know, every 3D package has its own way of dealing with materials/shaders. In ZBrush, reflectivity is a part of your native materials, and can be embedded within the texture. Other programs handle things a little bit differently.

    It's been asked many, many times before how you can export reflection maps from ZBrush (not to mention specular, etc.). I had always believed that it just wasn't possible -- until now. Today, I happened to have a brainstorm (yes, it hurt ), which led to a very simple technique that will finally let you export such maps!

    Here's how:

    For this tutorial, I'm going to build upon the Chapter 5 of the TextureMaster tutorial. As you know, that tutorial includes a segment toward the end where a different material is used to create a saddle across the rhino's back and cuffs on his legs.



    Here is the texture, also known as the color channel. To turn it into a bump map, you would simply press Texture>MakeAlpha and export the resulting Alpha for use in your program's bump channel. What's not visible on the color map is that there is also ZBrush material info embedded within the texture which gives the saddle a reflective quality. Once the texture has been wrapped onto the rhino, though, you can see the effect:



    All straight-forward so far. You've probably dealt with this many times before. What we're going to do now is convert the texture into a reflection map. Such maps use black for areas of no reflection, and white for areas of maximum reflection with various shades of grey possible in between.

    Of course, you could back the unwrapped texture and paint these colors. That takes a while, though, and in areas of broken-up reflectivity (such as rusting metal) would be a real pain in the...

    Fortunately, there's an easier way.



    First, export your model with the color map wrapped onto it. This performs several texture adjustments, which come in handy. You can also save the model, in case you want to do some other work later. Next, unwrap your texture onto the canvas (by selecting it and pressing Ctrl+F). Next, select the Colorizer1 material and save it.



    Now in the Material palette, click Show Used. This removes any material thumbnails which are not in use in the texture. It makes your life a little easier for what's to follow. In this case, you can see that there are 5 materials in use with TexturedMetal being the one that has the maximum reflectivity. Go ahead and select that material, then load the Colorizer1 material which you just saved over top of it.



    The Colorizer1 has both an S1 and an S2 channel. What we want to do now is go to the S1 channel and change Out to white. On your canvas, you'll see the saddle become grey in color.



    Since we want the saddle to be white (designating maximum reflection), we need to switch to the S2 channel. Here, changing the Ambient setting gives us many different shades of grey. A value of 100 goes to pure white.

    If your texture had other materials with various levels of reflectivity, you would repeat the material replacement steps for each of them. This model doesn't need that, though, so we'll move on to the materials which have no reflectivity:



    Again, you select one of the materials that's in use and load the Colorizer1 over top of it. This time, you change the In color patch to black. Repeat for each of the other non-reflective materials.



    When done, the result will be something like what is shown here. As you can see, there are a few places that didn't change. This is because they were the Flat Color material, which cannot be replaced. At this point, touch-ups are a snap! First, bake the layer. Next, use the Simple brush with RGB and no depth to paint over the problem areas:



    All done! Now use the MRGBZGrabber with AutoCrop turned off to capture the canvas as a new texture. Here's that texture wrapped back onto the model with a Basic Material:



    Because the reflection map was derived directly from the color map, it is a perfect match. Now we can export the model with this texture applied (to again take advantage of the texture adjustments). We now have a color map, a bump map, and a reflection map. And it only took a few minutes!



    Applied in C4D, these three maps allow you to render your ZBrush-textured models like never before. Specular and illumination maps could be created the same way.

    Of course, this was just a very simple example. I chose the rhino because he's a familiar character. But imagine a rusting monster robot, grunge maps on a dune buggy, or a derelict spacecraft. The possibilities are entirely up to your imagination.

    Have fun with it!

    Questions about using ZBrush? Check out these valuable resources:

    ZBrush Tutorial Movies: Link
    Download Center: (PDF documentation, models, plugins): Link

    Online Documentation: Link

    ZBC FAQ: http://www.zbrushcentral.com/faq.php
    ZBC Advanced Search:
    http://www.zbrushcentral.com/search....st&forumchoice

  2. #2
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    Thanks Matthew, I will give it a try!

  3. #3
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    thank you aurick, for putting together that detailed tutorial
    my fun with zbrush thread, my homepage riolama, and my zbrush blog

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    Nice piece of lateral thinking - thanks Matthew.

  5. #5

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    Now that is useful. I hereby bestow upon you the title of "Wizard" and all the privlidges attached to this title.

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    Thank's Aurick I'll have to try this out.

  7. #7
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    Exclamation

    YEA!

    I make maps for UT2003 mods!!!

    and they use spectacular and such tweaks for their shadder systems...

    The black and white (greyscale?) Mixmap I have been traceing manualy! this is realy a great time saver , plus it is perfect every time!!!

    WOOT! thanks M8!
    For Hire.

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