Sorry the Tartan plugin isn’t working…I’m not sure what version of AM it works on, it doesn’t say and I haven’t had a use for it yet.
Enhance AM has a plaid that you can check out here:
http://www.shaders.org/am_textures/am_plaid.htm
Unfortunately, it’s not part of the free stuff they have.
There’s a plaid located here:
http://www.staor.net/hasham/materials/materialPage.cfm?browseByType=procedural
You might be able to modify it for your purposes.



