Some Stereo workflow questions

[bencowell]

Hello,

We're looking into utilising the V-Ray Stereoscopic Helper for a project and I have a few questions about the workflow. There's a camera modifier plugin written by Louis Marcoux (available here), which has great visual feedback on comfort zones and the convergence point of the cameras.

I was thinking about wiring the output of the interaxial distance of this modifier into the V-Ray Stereo helper's eye distance so I have best of both worlds, ie a nice visual feedback on the effect via the modifier, but the simple side by side rendering of the V-Ray helper.

My question would does anyone have any detailed documentation or experience using the helper? .. I can pretty much guess what all the options do but I'd be really interested to see whether I'm going all round the houses to get interactive feedback on viewer comfort levels, if there's an easier way.

Any tips greatly appreciated.

cheers
ben

[bencowell]

I've been investigating further on this today, I'm really not sure that the Vray helper is performing as it should. Here's a visual explanation of what's going on :

If I setup my camera and preview my effect using the above modifier I get a really good stereo effect, I then input the exact Interaxial distance into the Vray helper, enable the helper and render from the central camera. I then get a completely different stereo effect, when I preview in the VFB using anaglyph I actually get a swapped left and right eye.

I'm baffled why they don't correspond. I'd expect a small amount of variation but the two effects just don't correspond in anyway. I can't find any documentation on the helper it all so I'm in the dark, so help would be appreciated.

[vlado]

There is a trick you need to do to make the helper focus at the camera target, if you are using a standard camera. You need to enable the "Get from camera" option in the DOF section of the V-Ray Camera settings (i.e. enable DOF, turn on the option, and disable it). Otherwise, the helper will use the amount that is explicitly specified (200 units by default). This is not an issue when using a V-Ray camera.

Best regards,
Vlado

[bencowell]

Thank you Vlado, I'll try that out tomorrow .. it's been sending me crazy !. Using a mix of your helper and Louis' interactive display is perfect as we get to see the likely results in the viewport but have the simplicity and speed of a side by side render.

cheers
ben

[bencowell]

Hi there,

The convergence worked a treat, however now I'm really struggling to get vray elements to work with EXRs and the stereoscopic helper. I get an embedded element for one eye but the other comes out looking garbled .. I'm using Tiled EXRs (after days of fiddling I realised that scanline EXRs don't seem to support embedded elements. Any help once again greatly appreciated.

[vlado]

Not sure about that one as it works fine for me (at least; the exr file has the correct info). But in any case, if you use the "Adjust resolution" option, try disabling it, and manually entering the increased horizontal resolution in the render settings. Or render to a .vrimg file and then convert it to OpenEXR.

Best regards,
Vlado

[bencowell]

Hi Vlado,

Thanks for your continuing help with this issue. I've tried setting the resolution by hand with no luck.

I suspect my issues could be linked with using the MaxEXR output menu in tandem with RPM, as I get my elements on an almost random basis, sometimes they're present, sometimes not, and sometimes garbled. I've been talking with Grant Adam about this issue over here and he's provided me a few clues. I'm going to try saving my files out via Vray and see if I have more luck.

Can you shed a little light on the the stereo helper works ?. Does it render two images from two temp cameras and comp them together as a post effect ? (which would explain the random nature the error as it's very similar to when I use two cameras, I get elements in one render and not the other on an almost random basis). Or does it create temp cameras and render them both at the same time ?.

thanks
ben

[vlado]

Can you shed a little light on the the stereo helper works ?. Does it render two images from two temp cameras and comp them together as a post effect ? (which would explain the random nature the error as it's very similar to when I use two cameras, I get elements in one render and not the other on an almost random basis). Or does it create temp cameras and render them both at the same time?

Nope, the helper does not create any additional cameras. Everything is done internally, it simply changes the way the camera rays are calculated. The "Adjust resolution" option might be a problem, since V-Ray changes the resolution after the rendering has started, which might be something that RPM or the 3ds Max OpenEXR saver do not expect. Now that I think of it, the "Adjust resolution" option only resizes the regular RGBA output buffer, but not any 3ds Max render element buffers.

Best regards,
Vlado

[bencowell]

Hi Vlado,

Well Grant solved my problem (I think !), I should have been saving my EXR's via V-Ray rather than via Max. His fix is on the RP Forum should anyone else be searching for it in the future : http://www.rpmanager.com/cgi-bin/yab...m=1278597588/0

Thanks for all your assistance, I think the issue was due to me not being up to speed on how one should save EXRs and then on the Vray Cache / Raw Manager feature in RPM.

thanks
ben