Tweet
Heya Folks,
One of the other folks I work with is doing a shot with a bubble in it - the bubble tears in slow motion at one point and how he's achieving this is by using a gradient ramp in the opacity slot to wipe off the bubble and then releasing particles as the edge wipes along.
What we've noticed though is when you put anything into the opacity slot, even if it's a pure white value (which should be totally solid and the same as not using the opacity slot at all) it seems to trip something in the vray material and dull the reflections if you look at the reflection filter channel. This only happens with the fresnel tick box in the material though.
1. If you make a default vray material, fresnel ticked on and give the reflection some strength and turn on the reflection filter element and do a render you'll get a normal looking falloff mask in the reflection filter slot.
2. Next put any white procedural into the opacity map slot - I used a gradient ramp or a vray colour, both set to pure white so the object is still totally solid. Render again and you'll get a dull looking reflection filter.
3. Lastly turn off fresnel in the vray material, this time put in a falloff map in the reflection strength slot and use the same fresnel ior as you had in the vray material. Leave the opacity map you had in previously, and when you render you'll get a normal looking reflection filter again.
So it seems like opacity maps seem to cause a problem with the fresnel calculations in the vray material which could cause problems with the likes of leaves or other things that use opacity maps?
Here's a crap reflection filter render of a teapot using
Left: a vray material with fresnel and nothing in the opacity slot
Mid: the same vray material with a white vray colour map in the opacity slot
Right; the same vray material with fresnel off, a falloff in the reflection slot and a white vray colour in the opacity slot.
And a max 2014, vray 3.12 file:
vray_fresnel_opacity_bug_m2014_vr3.12.max.zip
One of the other folks I work with is doing a shot with a bubble in it - the bubble tears in slow motion at one point and how he's achieving this is by using a gradient ramp in the opacity slot to wipe off the bubble and then releasing particles as the edge wipes along.
What we've noticed though is when you put anything into the opacity slot, even if it's a pure white value (which should be totally solid and the same as not using the opacity slot at all) it seems to trip something in the vray material and dull the reflections if you look at the reflection filter channel. This only happens with the fresnel tick box in the material though.
1. If you make a default vray material, fresnel ticked on and give the reflection some strength and turn on the reflection filter element and do a render you'll get a normal looking falloff mask in the reflection filter slot.
2. Next put any white procedural into the opacity map slot - I used a gradient ramp or a vray colour, both set to pure white so the object is still totally solid. Render again and you'll get a dull looking reflection filter.
3. Lastly turn off fresnel in the vray material, this time put in a falloff map in the reflection strength slot and use the same fresnel ior as you had in the vray material. Leave the opacity map you had in previously, and when you render you'll get a normal looking reflection filter again.
So it seems like opacity maps seem to cause a problem with the fresnel calculations in the vray material which could cause problems with the likes of leaves or other things that use opacity maps?
Here's a crap reflection filter render of a teapot using
Left: a vray material with fresnel and nothing in the opacity slot
Mid: the same vray material with a white vray colour map in the opacity slot
Right; the same vray material with fresnel off, a falloff in the reflection slot and a white vray colour in the opacity slot.
And a max 2014, vray 3.12 file:
vray_fresnel_opacity_bug_m2014_vr3.12.max.zip
Comment