Mirrors, Rendering times and Settings

[Skippydog]

Hey, I'm just working on a few renderings for a client and am having an issue with rendering times taking longer than they should. It's in the fwd head of a boat, which we did some renderings of the other day. There's a mirror on one side and we've just changed it to have another on the opposing wall. Since I've done that however my rendering time has gone up from 2 hours - 15+. I thought that I could turn one mirror off and render them separately, however that doesn't seem to have done much. Any chance anyone knows how to get around this?

I've attached the image with the location of the new mirror. The same wall now has a timber finish, but I don't think that should affect anything.



Also, what sort of times does it take people to render an image and what do you tend to do for allowing time to get them done? Do you do anything different for showing to clients via email/computer screen versus something that's specifically for print. Obviously printed materials need to be higher quality but do you reduce that if it's only going to be viewed on screen?




Regards
Chris

[Skippydog]

Re: Mirrors, Rendering times and Settings

Shameless bump. Is there no one with any ideas for this? I've found a workaround to get the rendering times down (turning all my lights off and putting the GI onto a flat white and setting it to 50000ish) but I'd love to know why this is.

Chris

[Micha_cg]

Re: Mirrors, Rendering times and Settings

No idea ... right, for example I never was in your render situation.

But your test gave me an idea - you used lights in your scene? Than the raytracing of this lights could be the problem. Do you use LC+IM? If yes, than you could try to use arealights and the light option "store with IM". If this dosn't help, avoid lights, but a HDRI env should be ok. Your scene looks like lights are not needed, a HDRI should do the job. Or you use emitter planes, if you need lights.

So far I understand, Raytracing is using a fixed amount of samples termimated by the subdivs and this can be quite slow for many light and maybe also for mirrors. GI based on random sampling independent from the colors of the HDRI or the count of emitters.

[thomthom]

Re: Mirrors, Rendering times and Settings

What's your Max Reflection/Refraction? (General Switches)

[Skippydog]

Re: Mirrors, Rendering times and Settings

Hi, thanks for the replies.

@Thomthom:
My Max Reflection/Refraction depth is set to 2.

@Micha:
I use QMC and LC. I havn't figured out the settings for IM yet. I've read that QMC gives the most accurate result, so thought I might aswell just use that.

I was thinking that it was to do with the raytracing, but thought that the GI would use it too. However it worked when I used the GI.

Heres one of the final views. Although my boss wanted the mirrors blurred, this is about how the render finished up.

[Micha_cg]

Re: Mirrors, Rendering times and Settings

I use LC+IM (+DE some times) all days, because QMC is much to slow for my need. At the tutorial section -> my starter kit you could find some thoughts more.

[Skippydog]

Re: Mirrors, Rendering times and Settings

Hi Micha,

I've been looking through that from time to time, now I just need some free time to have a bit more of a play around. :'(