Hi All,

I am trying to make a simple effect.
I have a sphere that I have added a color node to to make it red.
I have a RGBA PNG with alpha that has white grid lines and hollow spaces.

I have a mantra surface that is using the PNG file as a color map. I assumed the alpha would be honored but it is not. When I apply the material to the sphere object I get white grid lines and black solid areas.

So I apply the same map to the Opacity TAB and the sphere becomes hollow except for the grid lines. Is there a way to invert the alpha on the Opacity TAB?

What I want is red sphere with white grid lines.

I realize I could do this with two spheres, but shouldn't there be a way to accomplish this simple effect with one?

You could dive inside the surface material and use a mix node to combine the point color and the color map and drive the bias with the alpha channel.

Mantra Surface doesn't have a layer compositing paradigm like that. If you donät need anything else, the Decal material might do what you need?

I thought about the Decal preset but in one of the new training videos for R13 Ari Danesh mentions that we should just use Mantra Surface all the time because there are some new global variables, or something, that are built in for PBR.

I am not doing anything that advanced but I wanted to try to stay entirely in Mantra Surface. It would be nice if there was simply a way to invert a Map directly in the interface like most other 3D packages have in their material systems.

I guess I'll try the decal.

Dany Bittel's PBR Layered Material might be something you would like then, although itäs not free.
http://www.orbolt.com/asset/_danylyon::PBR_layered_material [orbolt.com]

wow..im really suprised. As a MAX user, trying to switch (partially) to Houdini i was needing the same feature with Mantra surface. So far about trying to reconstruct a 3ds max in houdini for learning purposes. Not having that option at mantra surface or a workaround for that in a procedural software with no limits is ridiculous in deed. Disapointed.

Agon Ushaku
Not having that option at mantra surface or a workaround for that in a procedural software with no limits is ridiculous in deed. Disapointed.

No need for disappointment! It took a few seconds to edit the MantraShader.

thanks Marty… it makes my first houdini-hours easier .