PPT acting funny

[timmatron]

I've been doing some tests with PPT in a couple of my scenes using high numbers of subdivisions. And the only time I have noticed this glitch is when the subdivisions start getting high, like 10,000 and above, or somewhere around there. Could be lower but I don't know for sure.

Anyways, I thought it was just my imagination for a while, but last night I know for sure that I saw this....I start my rendering using light cache for 1st & 2nd bounce, high subdiv. Things progress normally. After a couple hours, there are a few ticks on the progress meter & everything looks ok. Then I come back in a little while and the progress meter is back to zero! And its hard to tell whether or not there actually has been progress in the rendering or not from just looking at the quality.

One time when this happened a couple nights ago, I let it render through the night. When I got up & came to my computer, the progress bar still showed nothing, and right before my eyes, the rendering completed without any errors or crashes - all without showing any progress on the meter.

It's so weird. I'm trying to do some experiments with PPT, but I can never tell if its working right or not. Everything seems to be rendering OK, other than the loooong render times of course. But I really want to get this to work right, so I can, like a popular TV commercial says, "Set it and forget it!". Anybody else notice something like this?

Vlado, if you haven't seen this problem before I would be happy to mail you my scene. I'm using Viz 2005 & latest build, of course. Thanks.

(as a side note, I don't thing .png images work right with Firefox. I was trying to look at the examples in the PPT tutorial, and they just come up as code or something)

[vlado]

This is purely an interface issue. It happens because the progress bar can only handle reliably a certain number of items. An item may mean different things, but for ppt specifically it is a camera ray that is traced. The number of these rays can become quite large and may overflow the capabilities of the progress bar control.

This can happen in normal light cache modes too, as well as with photon mapping. In any case, it is an interface problem; hopefully we'll get to fixing it.

Best regards,
Vlado

[timmatron]

Ahh ok, thanks. Would be nice to have it fixed in the future just to get an idea of how much time is actually remaining.

[timmatron]

Next Issue:

PPT won't let environment light through glass. Here is a render of a scene with environment light and direct light.

This first one is with the glass on.


And this is with the glass turned off.


Can anybody else confirm this?

[RErender]

Do you have "Effect Shadows" checked for the glass material?

[timmatron]

Yeah, its just the standard EGZ glass. I didn't change anything about it.

[vlado]

I think you probably need more reflection/refraction bounces. Not sure if the Egz material limits these, or maybe you have overriden the value from the Global switches rollout. Also make sure Refraction caustics are ON in the Indirect illumination rollout.

Best regards,
Vlado

[egz]

egzVRayGlass has controls for reflection and refraction depth under the Advanced Glass Parameters rollout, try to increase the values here a bit.
Also, does your glass have thickness? egzVRayGlass uses absorption, so if your glass doesn't have a real thickness the absorption effect on the light rays will continue into the room, and they will lose all their light pretty fast.

[timmatron]

Also make sure Refraction caustics are ON in the Indirect illumination rollout.

That was it! Thanks. I never realized you had to have refract. caustics turned on for environment light to come through glass. Well now I know, and knowing is half the battle. GI JOE!