Prepass

[cristoforo]

What is the prepass that vray does before rendering an image that has a pre-calculated LC and IRR map? I do not remember it always doing this prepass. Is this an option? Should I have it on or off for an animation?

[Da_elf]

its when you have a material with interpolated glossies turned on

[cristoforo]

The setting within each material under the reflect glossiness? Is it faster with this on or off?

[Da_elf]

when it was first introduced a while back i used to use it alot. now i dont use it at all. other people probably still use it im guessing

[cristoforo]

OK...I turned it off. Now the IRR map goes fairly quickly, but the actual rendering is taking much longer! Getting very nervous about a Friday morning deadline! Have already had so many problems with this animation....already extended the deadline 10 days!!! I have already done 2400 frames of the animation......now I have the last 480 to do!

[ShaunDon]

Using glossy reflections in animations are always going to be time consuming at render. I make a point to only use them when it's a highly visible surface and makes a big impact on the material, otherwise I'll leave it as a faint straight reflection.

If you're just using glossies to get a highlight, you can uncheck "Trace reflections" in the Options of your material. This is nice for mullions and such, small objects that should have highlights though you'll never see a reflection on such a small surface.

Unfortunately changing materials 3/4 of the way through rendering an animation is very risky. You've got to be sure that it's not going to make a noticable difference. Best of luck!

Shaun

[cristoforo]

Luckily it is a different area of the animation....so I can play around with the material settings...I changed all my glossy reflections that were around ,75 to ,90...should make a difference, no? For the mullions I did as you suggested...turned off trace reflections. Hope all goes well....have to launch this IRR calculation!

[cristoforo]

After calculating the IRR map, could I further change reflections....less glossy or not glossy at all.....or would that mess up the rendering?

[Clifton Santiago]

I definitely notice a speed performance with interpolated glossies in stills, but be careful with interpolated glossies in animations. According to the vray manual: "Note that it is not recommended to use interpolation for animations, since this may cause severe flickering."

In fact for architectural animations I usually turn off all reflections that were glossies in the stills, since primarily I am using them to get specular highlights on building surfaces for more realistic environment color rather than for realistic materials. It saves a lot of time, and rarely is an architectural client going to be intently examining animation quality. Except brushed metal materials... I will leave them on for those. But not interpolated.

[cristoforo]

Learning alot with my first vray animation!!!