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c4d-Jack
11-26-2007, 12:00 AM
Hi,

to get familiar with the multitude of vRay's GI settings, I try to a red bedroom. By now, it looks like this (modeling is not finished yet, of course):

http://www.c4d-jack.de/darkside/vray/red_room/red_room_02.jpg

The render time seems quite long: 29:27 minutes on a Core2Duo E6400 (2x2.12 Ghz) with 2GB RAM, in 640x480. But I like how it's going.

Anyway, I can live with long render times. But what worries me more is the GI errors (dark stripes or pixels) in the corner and on the panel below the window, as well as in the curtain (at the buttom of the window). Also, the right poster produces two dark spots.

Furthermore, the mattress doesn't seem to drop a shadow on the wooden chassis of the bedframe, and I can't find out why.

Last but not least, the bed seems to fly above the floor, but it really doesn't, I checked it twice.

The long render time is definitely caused by the curtain. The shader doesn't seem to have much influence, but the geometry (not that heavy, just about 20.000 polygons) does. If I deactivate the curtain, the image renders in about 5 minutes. Too bad, because I want 4 more of those curtains on the upper bedframe.
Strange, that this curtain slows everything down so bad. When I rendered ivy in another image, the massive ivy geometry didn't cause such evil slowdowns.

Here are my questions:

1. Any tips or hints for an artefact free GI on detailled geometry (corner, panels and flying bed)?
2. What about the non-existant shadow of the mattress?
3. General tips about how to create geometry that doesn't slow down rendering that bad (curtain)?

Thanks in advance!

Best regards,
Jack

eMeL-ViZ
11-26-2007, 09:58 AM
Hi Jack,

Nice Bedroom. Why it is Red? :wink:

To 1 & 2 : Under GI Tab got to the Irradiance map an increase Hemispheric Subdivions and Interpolated Samples. I triple them most of the times. Of course after setting a higher GI Preset. I had similar Problems like you have. You can avoid the Problems mentioned in Question 1 and by Activating the Details. Under this Tab increase the "Subdivs mult". I am going to a extreme 1.0. Then at next Put Scale to "World" and use at least 20 cm. These values correspond directly to the "DMC Sampler" Tab. There you put the Noise Threshold to 0.05 and the Minimum Samples to 16. I don't know what to do with the Path Sampler. You can also play around with Thresholds "Intensity - Normal - Distance", but most of the times I am leaving them like they are. With this you can gain an Ambient Occlusion like effect, but more natural.

But beware. These will increase your Rendertime immense although the Result is really great and solves your questions 1 and 2 (more or less). These are no perfect solutions. I am still working on it.

For your Question 3 I have no answer.

Hope I could help,

Moe