How to make vray standalone read pre-baked vrmap/vrlmap?

[Fredrik Averpil]

Hi,

So this is perhaps rather a question regarding V-Ray standalone, but since we use the one that comes with V-Ray for Maya I posted it here in this forum.

Is it possible to make vray standalone read a pre-baked vrmap/vrlmap?

Something like vray -sceneFile=c:/tmp/testscene.vrscene -vrlmap=c:/tmp/my_vrlmap.vrlmap ...?
I can't see anything like that in here: http://docs.chaosgroup.com/display/V...d+Line+Options

[vlado]

The path to the GI caches is specified in the .vrscene file. Is there a particular reason you want to put that on the command line?

Best regards,
Vlado

[Fredrik Averpil]

Hm, I see. Well, perhaps it may be a "nice to have" feature rather than a "must have" feature. Let me explain.

We have automated a series of actions from within Maya such as baking, reading the baked maps, exporting to vrscene etc. All you do is tick the appropriate checkbox in our job spooler UI which spools a job into Pixar's Tractor, which is the render manager we use. In Tractor a tree of tasks is generated, so for example one task can make mayabatch export a vrscene from the maya scene, one task can bake the GI and when that is done the final frame rendering can commence, reading the GI maps. Tasks which haven't finished can be defined to block other tasks. When whole rendering job is done, the vrscene may be deleted automatically as it is no longer needed.

In order to save disk space, we just save the maya scene without any baking or exporting settings enabled. On the commandline we give mayabatch one or several pre render scripts, which initates e.g. GI map baking, GI map reading, vrscene export or sets up DR. This works really, really well.

However, I would love to eliminate Maya altogether at render-time and start using V-Ray standalone more. I was hoping I could just export a "vanilla" vrscene and later give it arguments on the commandline so that it would know to skip rendering altogether and just generate a GI map or if it should render images but read a GI map. But now when I think about it, it must be several arguments that I need to feed V-Ray standalone, as it's not only the map file itself...

Of course, a workaround would be to not export a vanilla vrscene, but instead export it twice. One with the GI baking settings enabled and one with the GI map reading enabled. I could then delete both of them (as the Maya scene would still be the "master scene") when the render job is done. So I guess that's a "workaround" which will work perfectly fine although the vrscene has to be exported twice and take up twice the amound to disk space.

Yeah, well. I realize the whole "there's so much to do and so little time" thing too ... so yeah, I don't think it's more important than a lot of other feature requests.

Although maybe it could be very interesting to explore the benefits of being able to provide e.g. a python pre render (or post render) script to V-Ray standalone. But that's a completely different kind of beast, I guess.

[vlado]

We do, in fact, have the Python pre-render thing already coded for V-Ray Standalone, perhaps it's high time we include it in the installation.

Another option for you is to use a tool like 'sed' (if you are on Linux; if you are on Windows I'm sure there are ports) to parse and process the .vrscene files as needed.

Yet another option, which has been on my mind for the longest time, is to allow overriding of any parameter from the .vrscene file on the command line. However this might take a while to code.

Best regards,
Vlado

[Fredrik Averpil]

Hm, yes sed could perhaps work. But it feels wonky to do manual edits on the vrscene without Chaos-approved tools in a way... Although yeah that could be worth exploring.

But if you have a python pre render thing already -- why are you keeping it to yourselves?!
I for one will be using it as soon as it gets available.

That third option of yours would of course be the cleanest for rendering parameters. But the Python pre render thing sounds like the most powerful solution and the one I would use first, especially if that's almost already in there.

[vlado]

Hm, yes sed could perhaps work. But it feels wonky to do manual edits on the vrscene without Chaos-approved tools in a way...

Hmpf, why not? They are text files, you can do whatever you like with them. Lots of projects were put together by cutting and mixing .vrscene files in weird ways

But if you have a python pre render thing already -- why are you keeping it to yourselves?!

Because it requires linking to Python, which makes things a bit more complicated. But we'll have to tackle this, one way or another. Will see what can be done about it.

Best regards,
Vlado

[Fredrik Averpil]

Hmpf, why not? They are text files, you can do whatever you like with them. Lots of projects were put together by cutting and mixing .vrscene files in weird ways

If you change how a vrscene is created, hopefully you also update the tools which could modify it. And I won't have to find out the hard way
Joking aside, yes of course a sed approach is completely fine. I actually do some of this already but with regular Maya Ascii files, but it's more of a regex-and-search-and-replace type of thing via python.

Because it requires linking to Python, which makes things a bit more complicated. But we'll have to tackle this, one way or another. Will see what can be done about it.

Sounds great. Looking forward to seeing some kind of python connection to V-Ray standalone.

[bigbossfr]

Python Scene Access with VRay Standalone can be a great feature.
I hope it will here quickly.