Vray trends for animation/stills and interior/exterior

[BrianKitts]

I was curious as to what the trends are for vray settings right now in regards to primary and secondary bounces. For instance.... for the longest time I was using irradiance map for primary and QMC for secondary, but now I'm a huge fan of light cache as a secondary bounce, both for interior and exteriors.

 

I'm about to start doing some animation work again, and I'm wondering if I'm going to have any problems with using lightcache instead of QMC like before. Anyone have any experience with lightcaching for animation?

 

What's everyone else using and why do you think its the best route?

[Craig Ramsay]

For interior stills im usually using IR map/Lightcache, exteriors are really dependant on a few things but mostly IR map/QMC.

 

As for animation lightcache is great, it's usually faster than using IR map/QMC and you don't get many artifacts. There's a tutorial here to get you started if you haven't used lightcache for an animation before:- http://www.spot3d.com/vray/help/VRayHelp150beta/tutorials_imap2.htm

[BrianKitts]

awesome... always good to hear when you're switching to a better method.. thx

[ShaunDon]

For exteriors lately I've been sticking to QMC+QMC -- especially on detailed models lit by sunlight, you get a huge amount of detail in shaded areas that is nearly impossible to achieve with the irradiance map or light cache.

 

On interiors right now I'm using QMC+Light Cache. Again, I would opt for QMC+QMC if we had the farm to handle it since there is simply no beating the image quality, but once you pile on all those lights and glossy reflections inside an enclosed 3D scene, you really need the light cache.

 

For animation, I've been sticking to irradiance+QMC on the majority of my passes, save for cars which I render at QMC+QMC. I wish I could use the lightcache more in animation work, but we try not to have static scenes as they're pretty boring, and while Vlado's comping tut is most excellent I've not yet committed to using the method in production.

 

Shaun

[jophus14]

This is probably a stupid question, but I don't know what "lightcache" is. I have Irr map, QMC & Lightmap as options, but no Lightcache. Why is that?

[ShaunDon]

What version of VRay are you using? The light cache was added somewhere around 1.46.xx -- if you're running 1.09 or an early beta version you won't have it. Download the latest public release (1.47.03) from Chaos and you'll find it.

 

Shaun

 

(edit) I should add, if you're gonna upgrade don't do it while you're in the middle of any project you can't afford to start over. From 1.09 to 1.4x Vlado changed the way a lot of settings behave, so older scenes become almost non-renderable. It's painful, but trust me it's very worth it.

[jophus14]

Yeah i have version 1.09............Thanks for the reply. Is Lightcache that much better for exterior renders or is it personal preference?

[ShaunDon]

The light cache is the inverse of photon mapping... rather than tracing rays from the light source(s) to the camera, it traces them from the camera back. It's a faster method of globally working out light bounces, and as a bonus you can also cache the rays and use them when calculating glossy reflections.

 

The light cache generally will achieve results as good as the irradiance in less time. QMC will always be more accurate as it calculates out everything with brute force rather than taking shortcuts. The light cache can also be used for animations with no secondary motion (only the camera moves) -- which is an incredible bonus if you can use it, since it drastically speeds up the time it takes for the irradiance calculations and shortcuts the glossies.

 

Generally I opt for QMC+QMC. If that's too time consuming, I'll do QMC+LC. One other caveat to the LC is that it often can't handle standard mats -- so if I need to use non-vray materials to any great degree, I go back to irradiance+QMC.

 

Shaun

[Craig Ramsay]

This is probably a stupid question, but I don't know what "lightcache" is. I have Irr map, QMC & Lightmap as options, but no Lightcache. Why is that?

 

Lightmap and Lightcache are the same thing, Chaos just changed the name to lightcache to stop it getting confused with something else You should upgrade your version to the latest beta

[jophus14]

I think i might have to. It took me forever to get the version that i have now, but i guess i'm gonna have to keep up if i wanna learn.

[ShaunDon]

I've been on the beta for at least a year now and I highly recommend it. A lot has been improved under the hood since 1.09 that has allowed us to reduce render times while increasing image quality. But I really have to stress that it's not an easy transition -- not only will scenes visualized in 1.09 render very differently or not at all under the beta, but you also will need to tweak materials in your existing library.

 

I guess the math that drives much of the subdivision settings in the QMC was rewritten, so now you can achieve comparable quality with much lower settings. But this will also cause scenes and materials with values set for 1.09 to take much, much longer to render.

 

Good luck!

Shaun

[Ray]

What QMC settings do you use for your final QMC + QMC renders?