bump maps

Mixing displacement and multiple bump maps by Xuan Prada

A very common situation when look-deving an asset is combining various displacement and bump maps. Having them in different texture maps gives you the possibility to play with them and making very fast changes without going back to Mari and Zbrush and waste a lot of time going back and forward until reaching the right look. You also want to keep busy your look-dev team, of course.

While ago I told you how to combine different displacement maps coming from different sources, today I want to show you how to combine multiple bump maps, with different scales and values. This is a very common situation in vfx, I would say every single asset has at least one displacement layer and one bump layer, but usually, you would have more than one. This is how you can combine multiple bump layers in Maya/Arnold.

  • The first thing I'm going to do is add a displacement layer. To make this post easy I'm using a single displacement layer. Refer back to the tutorial I mentioned previously on this post to mix more than one displacement layer.
  • Now connect your first bump map layer as usual. Connecting the red channel to the bump input of the shader.
  • in the hypershade create a file texture for your second bump layer. In this case a low frequency noise.
  • Create an avergage node and two multiply nodes.
  • Connect the red channel of the first bump layer to the input 1 of the multiply node. Control the intensity of this layer with the input 2 of the multiply node.
  • Repeat with previous step with the second bump layer.
  • Connect the outputs of both multiply nodes to the inputs 3D0 and 3D1 of the average node.
  • It is extremely important to leave the bump depth at 1 in order to make this work.

Dealing with normal maps in Softimage by Xuan Prada

Yes I know, working with normal maps in Softimage is a bit weird sometimes, specially if you worked before with 3D Max normal+bump preset.

I’ve been using the same method over the years and suited fine for me, maybe would be useful also for you.
I prefer to generate the normal maps inside Softimage rather than Mudbox or Zbrush, usually works much better according to my tests with different assets.

  • So, you should import in the same scene both geometrys, high and low. Don’t be afraid of high poly meshes, Softimage allows you to import meshes with millions of polygons directly from Mudbox or Zbrush.
  • With both meshes in your scene be sure that they are perfectly aligned.
  • Check the UV mapping of the low resolution mesh.
  • Select the low resolution mesh and open the ultimapper tool.

- The most important options are:

  • Source: You have to click on your high resolution mesh.
  • Path: Where your normal map texture will be placed.
  • Prefix: A prefix for your texture.
  • Type: You can choose between different image formats.
  • Normal in tangent space: The most common normal map type.
  • Resolution: Speaks for itself.
  • Quality: Medium it’s fine. If you choose high the baking time will increase a lot.
  • Distance to surface: Click on Compute button to generate this parameter.
  • Click on generate and Softimage will take some time to generate the normal map.
  • The normal map is ready.
  • Hide your high resolution mesh.
  • Grab one of the MR shaders and drag it to your mesh.

- Use a normal map node connected to the bump map input of the shader.

  • Choose the normal map generated before.
  • Select the correct UVs.
  • Select tangents mode.
  • Uncheck unbiased tangents.
  • Hit a render and you’ll see you normal map in action.
  • Cool. But now one of the most common procedures is combining a normal map with a bump map.
  • I’m using the image above.
  • If you use a bump map generator connected into the bump map input you will have a nice bump map effect.
  • Find below the final render tree combining both maps, normal and bump.
  • The first bump map generator has two inputs, color matte which is a plain white color and the normal map with the options which I already commented before. Be sure to select relative to input normal in the base normal option of the bump map generator.
  • The second bump map generator is your bump texture where you can control the intensity increasing or decreasing the factor value.
  • The vector math vector node allows you to combine both bump map generators.
  • Connect the first bump map generator  to the first input and the second one to the second imput.
  • In the operation option select vector input1 + vector input2.
  • Final render.