Currently there are some known issues when using mental mill shaders in 3ds Max. mental mill shaders will render in the 3ds Max material editor and viewport if you follow these rules.
While I was at EUE last week I had the pleasure of talking with Ruediger Raab and Neil Hazard who are partly to blame for this fantastic new viewport rendering in 3ds Max 2010. They both made presentations which included a section on using mental mill shaders with max and they highlighted the some ‘caveats’ and some work arounds that will help you to get your mental mill shaders 3ds Max.
1. contain your material in a phenomenon with a single output for the final node and a single output for the result.
Sounds complicated, but it’s not. When you finish a shader, group it into a phenomenon before saving it for use in max.
If the last node in the phenomenon has more than one output, for example like the illumination_phong then add one more node that has a single output, like a math_colour_add.
Also, make sure that there is only one output on the result of the phenomenom.
This will be fixed in later releases.
2. Express UV coordinates explicitly.
When you use a lookup texture node to load a texture you must assign it UV coordinates. Just wire a state_texture_coordinate node to the texture UV slot on the texture lookup node.
Ruediger suggested that we group this into a phenomenon and save this back the the mm palette for use whenever we need to use it. Good thinking.
3. Scene settings.
Access the scene settings from the render drop down menu;
render | scene settings
From here you can add light nodes from your mental mill palette and one environment shader. I’ve added three point light nodes and changed their intensity and colour.
I’ve then added the lights to the scene by clicking add light button in the scene settings dialog. You can then change the lights position. This is a process only undertaken by the adventurous as you may find it difficult to control. I’ve placed mine in a basic three point layout with a key light and two coloured lights, a warm one at the front right and a cool one lower and from the back. The lights help us see what the shader looks like in mental mill.
Finally I’ve specified the environment shader in the scene setting dialog using the environment shader drop down list. The environment shader will be used in the 3ds Max viewport to create faked reflections. When we render the scene with mental ray the reflections will be ray traced.
Now save this scene and use it as a template when you want to start a new mental mill shader. You can download this mental mill scene set-up from here
4. Mental Ray wont always reload the mental mill material when rendering in max.
There is scurrently a bug in mental ray that causes the renderer to re-use a cached version of the mental mill shader. If you change the mental mill shader in mm and reload it in max then your viewport and material editor should update. The problem is, that when you hit render then mental ray may use the older version it has in memory. You will need to force mental ray to reload the shader by either 1. re-starting max, or 2. saving the mental mill shader with a new name and re-selecting it in the DirectX material in 3ds Max.