Sprites and Ambient occlusion problems

[Ungoliant]

Hello people, i have this problem i dont know how to solve, ambient occlusion dont recognize the alpha channel, i rendered a colored test, so you can see the grid shadow form in the floor.

Help please!!!, anyone

[Macha]

If you use the basic_occlusion material and dive inside you notice that there is no alpha going to the output.

I am no expert in shaders but a hack to get it working is to connect the surfacecolor node's alpha to the output node's opacity. You have to adjust or disconnect the colorMapIntensity.

Another thing you could try is to use a basic shader and then PBR or a light source with samples.

[Ungoliant]

I have a custom shader and i tried with ambient occlusion, the problem is that the ambient occlusion evaluates before than the alpha channel, i tried too with light template and global illumination vex shader, but has the problem showed in the first post

[rende]

Don't know if this would help but here goes.

Why not use the trace node using the alpha texture to cut out the unneeded geometry and just copy stamp that instead of using sprites?

[realer]

hi .. well i`m not sure but i had this before and if i remember correctly the vm_sfilter (sample filtering) set to opacity filtering fixed it..

so go to your mantra rop . edit rendering parameters, add vm_sfilter -> set it to opacity filtering

hope this helps

[Spyrogif]

i didn't explore the houdini shader part enough to give you the right way to follow but i get a quite similar problem with maya and mental ray.

To fix this i plug the occlusion directly in a constant node color and apply my cutout map in this constant transparency .

i hope it can help

[anim]

vm_sfilter rendering parameter is set to opacity by default so i guess it will not help in this case

but

Light template and VEX GI light should work but you need to set it to Transparent Ambient Occlusion

you can also use occlusion() function in surface shader, but the VOP form doesn't have that option so you need to use VEX or Inline VOP then you can use "samplefilter" option and set it to "opacity"

[Ungoliant]

Hello thanks for your help,

Realer:I have the same problem with vm_sfilter -> set it to opacity filtering,

rende: i have a lot of sprite, and with trace sop and various material my houdini will die.

anim: Light template and VEX GI light with Transparent Ambient Occlusion, i have the same problem, maybe my shader dont work

im keep trying

thanks for your time

[ykcosmo]

If you bake your sprites into point cloud, then use point cloud based occ, it might work.