Material Override Excluder
Do you use the Vray Material Override to do chalk renders and wish that it would allow you to exclude certain materials? Like VRayLightMtl and any refractive materials like glass? Well now you can using this little script. It sets up a Shell Material which allows you to switch from one material setup to another. So even if those pesky VRayLightMtls and refractive materials are within Multi-sub materials then you’ll still be able to exclude them. Give it a go, test it out and let me know how it works for you! Cheers to Fraggle from the Chaosgroup forums for giving me the motivation to do this one. It should be easy enough to hack it for Mental Ray or other renderers, feel free to ping me a message with any specific requests, I'll add Corona soon.
Choose the Material Editor Sample Slot you want to get your Override/Chalk Shader from, that’s down bottom left in Slate or one of the sample slots in the Compact-Material-Editor. Keep the excludes on for whichever materials you want to preserve (let me know if you want more there). You can keep refractive materials and automatically desaturate refraction / fog / exit colour/maps. You can choose to keep opacity maps/bump maps/ displace maps this will work with nested materials, multi-sub, VrayBlends etc… You can also exclude by a material name, and using Wildcards you can exclude all materials which have glass in their name for instance by putting in *glass* into the name exclude box. You can also get your the objects you have in your include/exclude List in the VRay Material Override Exclude Dialog. Press ‘Create Override Setup’ and your scene is now ready to render with override materials on, you can press ‘Go Material’ at any point to return to the original materials, and press ‘Go Chalk’ to go back to rendering chalks. Press ‘Remove Override Setup’ to revert back to how your scene was, even if you close and reopen the script. Hold Shift on the ‘Go Override’ and ‘Go Material’ buttons to turn just the selected objects to Override or Material.
Download the MCR File Run it using the Maxscript(now called Scripting in 2016) Menu -> Run Script or Drag and drop it from your hard drive into the viewport.
You'll find the macro under 'DW Tools'
v.1.2 Updated to fix, bug when not using Vray Material Exclude List, and extra layer of warning messages added.
v.1.3 Updated to add override to objects with no materials.
v.1.4 Update to allow overrider of XRefScene Materials, and exclude by name can have multiple inputs using commas to separate.