LC camera path glossy rays question

[peterguthrie]

When using the light cache set to camera path, can we still use it to calculate glossy rays, or will it not work?

I notice in the rendering an anim II tutorial (http://www.spot3d.com/vray/help/200R...ials_anim2.htm) it tells you to turn off the secondary bounces GI when doing the actual rendering.

[Morne]

I think this is because it will already be "baked" into the IR Map - sort of from the calc phase?

[peterguthrie]

yeah thats my understanding, i was just wondering if you can tick the glossy rays box and then load it from file when doing the final rendering.

[Morne]

I understand it that you won't have to tick the box or use it AT ALL with the final rendering. Asif the Lightcache and glossy rays was saved/combined into the IR map with the calc in phase1 and not seperate as we would do it traditionally - I think?

[peterguthrie]

ah ok, wasnt sure if glossy rays could be saved into the irradiance map, i guess i better do some tests then...

[Pictor2]

far as I know glossy rays are not saved into the irr map though being not exactly technically minded I could be wrong..

I have done several animations where the light cache was 'burned' into the irradiance map during the pre-calc and then secondary bounces set to none for the final output and I always uncheck 'use LC for glossy rays' and so far they've all come out fine. If you do have a scene with a lot off glossy surfaces and you need to speed up the rendering I'd set primary to irr map (multiframe inc every 10th frame or so), secondary to LC in 'Fly through mode' and turn on 'Use LC for glossy rays' and save out seperate .vrmap and a .vrlmap for use in rendering the final frames. This way the light cache can be used to accelerate glossies.

[Morne]

far as I know glossy rays are not saved into the irr map though being not exactly technically minded I could be wrong..

I have done several animations where the light cache was 'burned' into the irradiance map during the pre-calc and then secondary bounces set to none for the final output and I always uncheck 'use LC for glossy rays' and so far they've all come out fine. If you do have a scene with a lot off glossy surfaces and you need to speed up the rendering I'd set primary to irr map (multiframe inc every 10th frame or so), secondary to LC in 'Fly through mode' and turn on 'Use LC for glossy rays' and save out seperate .vrmap and a .vrlmap for use in rendering the final frames. This way the light cache can be used to accelerate glossies.

Yes but Peter was referring to the "New tutorial" where you do a IR Map precalc and light cache calc for EACH FRAME in "precalc" mode for phase1 and then just use the IR Map for phase2 which is the actual rendering

[peterguthrie]

I'm trying to do a short clip where the camera moves forward slowly and the lighting changes.

[Pictor2]

ah righto, sorry. Similar principle though surely? If you've got 'use light cache for glossy rays' checked you will need to save the LC from phase one and load it into the secondary bounce for phase 2 so vray has something to calculate glossies from? Switching secondary to 'none' surely won't work when using LC for glossies, far as I know glossy rays are not stored in the irr map. Might be different of course for this newfangled camera path option but doesn't seem to be mentioned in the tutorial.

[peterguthrie]

then I'm kind of back to my original question

The tutorial I linked to above seems to me to be the best approach for the clip I want to render, but can I modify the workflow so that the LC helps with the glossy rays?, as without it it seems very slow.

OR, should I just stick with Brute force and LC and accept the long render times?

[vlado]

If you plan to enable the "Use light cache for glossy rays" option, then you need the light cache for the final rendering. That means that, for animations with moving objects, you'd have to keep the light cache to "single frame" mode along with the "Use camera path" option enabled.

If the "Use light cache for glossy rays" option is disabled, then you can turn off secondary bounces altogether.

Best regards,
Vlado

[Morne]

If you plan to enable the "Use light cache for glossy rays" option, then you need the light cache for the final rendering. That means that, for animations with moving objects, you'd have to keep the light cache to "single frame" mode along with the "Use camera path" option enabled.

If the "Use light cache for glossy rays" option is disabled, then you can turn off secondary bounces altogether.

Best regards,
Vlado

That's something that SHOULD be added into that tutorial and ALSO in the documentation

[peterguthrie]

If you plan to enable the "Use light cache for glossy rays" option, then you need the light cache for the final rendering. That means that, for animations with moving objects, you'd have to keep the light cache to "single frame" mode along with the "Use camera path" option enabled.

If the "Use light cache for glossy rays" option is disabled, then you can turn off secondary bounces altogether.

Best regards,
Vlado

Thanks Vlado, thats what I needed to know.

[ruud3dv]

And can a precalculated lightcache (one single frame with 'Use camera path') be used for glossy rays in a scene without moving objects then? Or does the lightcache always need to be calculated on single frame for each frame to use that?

Does the option have to be enabled both during precalc and rendering?

[vlado]

And can a precalculated lightcache (one single frame with 'Use camera path') be used for glossy rays in a scene without moving objects then?

Yes.

Does the option have to be enabled both during precalc and rendering?

It shouldn't matter, but just for consistency it's probably best to keep it the same.

Best regards,
Vlado