Another of those steps that I need to do when I’m working on any kind of vfx project and I consider “a must”.
This is how I set up my Zbrush displacements in Modo.

- Once you have finished your sculpting work in Zbrush, with all the layers activated go to the lowest subdivision level.

 

 

- Go to the morph target panel, click on StoreMT and import your base geometry. Omit this step if you started your model in Zbrush.

 

 

- Once the morph targer is created, you will se it in viewport. Go back to your sculpted mesh by clicking on the switch button.

 

 

- Export all the displacement maps using the multi map exporter. I would recommend you to use always 32bit maps.
- Check my settings to export the maps. The most important parameters are scale and intensity. Scale should be 1 and intensity will be calculated automatically.

 

- Check the maps in Nuke and use the roto paint tool to fix small issues.

 

- Once in Modo, import your original asset. Select your asset in the item list and check linear uvs and set the amount of subdivisions that you want to use.

 

- Assign a new shader to your asset, add the displacement texture as texture layer and set the effect as displacement.
- Low value 
and high value should be set to 0 and 100.

 

- In the gamma texture options, set the value to 1.0
- We are working in a linear workflow, which means that scalar textures don’t need to be gamma corrected.

 

- In the shader options, go to the surface normal options and use 1m as value for the displacement distance. If you are using 32bit displacements this value should be the standard.

 

- Finally in the render options, play with the displacement rate to increase the quality of your displacement maps.
0.5 to 1 are welcome. Lower values are great but take more time to render, so be careful.

 

- Render a displacement checker to see if everything works fine.

If you look through my blog you will find a lot of posts talking about linear workflow, gamma correction and other colour related stuff using different 3D apps.
Someone ask me on twitter about it and I’d like to answer here with a quick practical example.

Question: He Xuan, do I need to gamma correct a 16bit floating point ptex texture if I’m working in a linear workflow?
Answer: Nope, yo don’t. It’s linear 1.0 which means is already in a linear workspace.

That said, let me explain it to you with a quick and simple case scene.

If the inputs are .hdr or .exr 16bit or 32bit images, they don’t need to be gamma corrected. If you are using sRGB 8bit maps with a 2.2gamma baked, then you need to gamma correct them.

 

I have here two different nodes in Nuke. Both of them have the same cropped image from an 32bit floating point .exr panorama. I saved them as two different files, one of the nodes is a 32bit .exr (linear 1.0) and the other one is an 8bit .tif (sRGB 2.2)

I’m using both images in two different VRay shaders in Maya.

 

I created two small grids, and I applied the shader with the linear image to the grid on the left, and the shader with the sRGB image to the grid on the right.
This is what I got if I render the scene.

The sRGB doesn’t look right. It needs to be gamma corrected.
With a gamma correction node with value 0.455 (1/2.2) should be fine.

Render again, and everything looks as expected.

You have probably experienced this error a few times already, haven’t you?
It is quite common specially when you are working with huge assets.

It happened to me last week a lot of times when working with a 40 UDIM asset and trying to export a 32 bit displacement maps.
My machine couldn’t handle it and Zbrush started to giving error saying “Insufficent memory error”.

If this happens to you and don’t know how to extract your displacement maps out of Zbrush, don’t worry, this small trick could help you.

- Execute Zbrush using your root account in Mac or Administrador account in Windows.
- In Windows just right click on the Zbrush icon and select “run as administrator”.
- In Mac start a terminar and logging as root.
- Then execute Zbrush.

- Then in Zbrush go to Preferences -> Mem and increase the Compact Memory.

-That’s it. It should work now.
- Unfortunately this trick only worked for me with simple displacement, but it didn’t work with vector displacement :(

Zbrush to Maya and Vray 2.0

December 1, 2013

I know how tricky can be sometimes to make your Zbrush displacements look great outside Zbrush.
Maya, Softimage, Vray, Renderman or Arnold, just to name a few treat Zbrush displacements in a different way.
Let me explain to you my way to export displacement from Zbrush to Maya and Vray 2.0

- First of all, if you are working with a final asset you will have to export your displacement using your base geometry imported in Zbrush. If you did the scult from scratch in Zbrush you may want to export your lowest subdivision mesh, create a good uv mapping and re-project your sculpted detail in that mesh.
If this is the case, check this.

- Go to the lowest subdivision level.

- Turn off all your layers.

- Export as .obj

- This is the object that you are about to render. If you had imported a base mesh before, you won’t need to export it again, it would be in your 3D application already.
- Go back to the highest subdivision level.

- Turn on all your layers.

- Go down to the lowest subdivision level.

- Store a new morph target and import the previous exported .obj or your original base mesh from your 3D application.

- Your sculpted model will be substituted by the original mesh with no sculpt information.
- Click on switch morph target to activate again your sculpted mesh.
- You are ready to export the displacement maps, just check my settings below for 16 bits, 32 bits and vector displacement.

- Finally to set-up your shaders and render settings for Zbrush displacements in Maya and Vray 2.0 check my previous post about it.

Arm texture breakdown.

September 19, 2013

I did a simple and quick texture breakdown for an human arm.
These are the textures that I usually create when I need to texture digital doubles for films or any kind of humanoid character.

These are the most basic textures used.
Usually working on movies we need more additional textures depending on render engines, other pipeline tools or artistic decisions.
But as I said, take this example as a base or starting point for your work.


These are quick renders using a neutral lighting rig for look-dev.


Diffuse textures.


Overall textures.


Scatter textures.


Displacement textures.


Fine displacement textures.


Specular textures.

 

 

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