Support for transparency.

[petermcevoy]

This feature request was mentioned in issue #2.

[sharktacos]

Two thoughts to consider here:

First, I'm thinking that the transparency should effect the gaps in between the yarns created by yarnsize lower than 1. That is, when a fabric appears "see through" this is not because the threads are transparent, but because of the gaps between the threads. I'll see if I can share some test renders showing this with the shader.

In that case, perhaps the transparency should simply be a on/off checkbox. So off is black gaps (the current behavior) and on is 100% transparent gaps. I don't know that it makes sense to have 50% transparency here. What do you think?

Second, Vray 3.6 now has three methods for calculating opacity that you may want to look at.
https://docs.chaosgroup.com/display/VRAY3MAYA/V-Ray+Material+%7C+VRayMtl#V-RayMaterial|VRayMtl-BasicParameters

The opacity modes are:

Normal – The opacity map is evaluated as normal: the surface lighting is computed and the ray is continued for the transparent effect. The opacity texture is filtered as normal.

Clip – The surface is shaded as either fully opaque or fully transparent depending on the value of the opacity map (i.e. without any randomness). This mode also disables the filtering of the opacity texture. This is the fastest mode, but it might increase flickering when rendering animations.

Stochastic – The surface is randomly shaded as either fully opaque or fully transparent so that on average it appears to be with the correct transparency. This mode reduces lighting calculations but might introduce some noise in areas where the opacity map has gray-scale values. The opacity texture is still filtered as normal

[petermcevoy]

Thank you. That is helpful!

…

On lör 16 sep. 2017 at 18:40, sharktacos ***@***.***> wrote: Two thoughts to consider here: First, I'm thinking that the transparency should effect the gaps in between the yarns created by yarnsize lower than 1. That is, when a fabric appears "see through" this is not because the threads are transparent, but because of the gaps between the threads. I'll see if I can share some test renders showing this with the shader. Second, Vray 3.6 now has three methods for calculating opacity that you may want to look at. https://docs.chaosgroup.com/display/VRAY3MAYA/V-Ray+Material+%7C+VRayMtl#V-RayMaterial|VRayMtl-BasicParameters <https://docs.chaosgroup.com/display/VRAY3MAYA/V-Ray+Material+%7C+VRayMtl#V-RayMaterial%7CVRayMtl-BasicParameters> The opacity modes are: *Normal* – The opacity map is evaluated as normal: the surface lighting is computed and the ray is continued for the transparent effect. The opacity texture is filtered as normal. *Clip* – The surface is shaded as either fully opaque or fully transparent depending on the value of the opacity map (i.e. without any randomness). This mode also disables the filtering of the opacity texture. This is the fastest mode, but it might increase flickering when rendering animations. *Stochastic* – The surface is randomly shaded as either fully opaque or fully transparent so that on average it appears to be with the correct transparency. This mode reduces lighting calculations but might introduce some noise in areas where the opacity map has gray-scale values. The opacity texture is still filtered as normal — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#13 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAHGLAJDC4KBwO4enTCCsAbPeWOe1jdhks5si_oSgaJpZM4PZ28z> .

[sharktacos]

Here's an initial test showing (on the right) 100% opacity in the gaps between the yarn strands caused from lowering the yarnsize, and the normal behavior where these gaps are black (on the left). This is a pretty coarse weave. I'll do more tests on finer weaves (i.e. larger values for the UVsize)

[petermcevoy]

Support for this has been added in PR #37.
Still need to look att exposing it correctly in Maya.