Toggle alpha display, render faster

[PowerCreative]

I couldn't find this posted anywhere, but we've noticed that when we turn on the alpha display during render, the image renders significantly faster, or rather, it draws much faster. So we often have alpha display toggled on. Has anyone else noticed this?

And just out of curiosity, why does this happen?

[Morne]

That doesnt sound right, but I'll be sure to check it out with my next big render

[vlado]

Is that in the 3ds Max frame buffer, or the V-Ray one?

Best regards,
Vlado

[PowerCreative]

I always use VFB, but the other guys typically don't. And it appears to have the greatest impact in large scenes... could this be a hardware thing? We're all on high-end Boxx systems. When I get some free time I'll try to get a reproducible test scene together.

[svetlozar.draganov]

Fell free to send us the scene - we would like to test it in our environment.
Thank you very much in advance.

[PowerCreative]

Alright, so I've been unable to reproduce. My coworkers haven't either, one seems to think it stopped rendering faster with alpha after the last Max PU... but we noticed this happening for about a year. I think we're all delusional. If a scene turns up, I'll send it in.

[PowerCreative]

Sorry for the bump - just had to followup.

Toggling alpha does indeed make the render go faster, IF you're using Max's default frame buffer. If you're using VFB, you will not notice any difference. I just realized that the other guys never use VFB (why not?!) but I always do. Not a vray thing, really, but there it is.

[alexyork]

That is very interesting....... we always use the VFB of course so never noticed this.

[3LP]

Yeah but...

We are using the VrayFB as allways as well, but not for our final renders...
RPManager desactivate the VrayFB so that all the passes are rendered and saved correctly, so does that mean that all our production final renders are rendering slower then our previews?

Woaw...

Stan

[svetlozar.draganov]

According to my tests - the delay only occurs if Max Frame Buffer is activated, with both VFB and MaxFB off there is no such delay.