imagePlane affected by environment override?

[jasonhuang1115]

Hi,

I used a example scene posted by Zdravko to test integrating CG and live-action plate. In the example scene, everything works fine as the live-action plate projection was connected to both the Background texture in the Environment tab (render setting) and the Environment Override of the SG node of VRayMtlWrapper.

However, if I use an imagePlane, it seems not working. In my test, the imagePlane got affected by the Environment Override set in the VRayMtlWrapper (become darker). If I unticked the Environment Override, the imagePlane renders correctly but then I lost the matteShadow effect that I need for integration.

Here is the example scene and a render to show the problem.

MtlWrapper_Example_02_question.zip

Did I miss something or if there is a workaround?

Thanks.

[chuckie7413]

when you use the image plane you then have a doubling up effect of the background image as you have it already connected to your background slot. If you want the image plane in your viewport still I normally create a pre and post render mel script that just turns the visibility of the image plan on and off. Off when rendering and on when render finishes.

I have not used vray for a while but i thought chaos introduced a way to map see the background texture within the viewport without having to create an image plane. I could be wrong though.

Best,

Rich

[jasonhuang1115]

I see. I hope the dev. team can improve this workflow to achieve something like what you can do with the matteShadow shader in mental ray.

Thanks Rich.

[chuckie7413]

Yeah I would really like to see the chaos team make this approach more user friendly. It is really awkward to set this up currently.

Thanks,

Rich

[Morbid Angel]

are you doing the final integration of your render right out of maya? will you not use a comp software to final the render? in any case I think the contribution to the illumination is done by gi. If you set the gi ray distance to a distance of your shadow for example in my case 10 units, that helps to reduce the overall illumination of the plane. Its not a solution but may give you a temporary workaround.

[jasonhuang1115]

Thanks for chiming in, Dmitry. I was referring to the process of doing lighting and look-dev in Maya. I would like to see the plate when doing test rendering. I did some tests with the ray distance trick. If set too low my CG got noticeably darker; too high then the over bright imagePlane crept in. Any tips on set this GI ray distance efficiently? Guess it's gonna be between the depth of the imagePlane and the furthest possible I want the GI ray to travel?

[Morbid Angel]

well we do lighting on image planes all the time. The gi is not a deciding factor in the look however since we always render the shadow/gi pass separately anyway. Im used to idea of looking at my render strictly in nuke, after setting up some lighting in maya. Keep in mind that the color of the image plane is not accurate when its viewed with sRGB so you can get it close but the final correction is done in comp.

[jasonhuang1115]

Thanks Dmitry. What bothers me a bit is the the very noticeable edge between the matte shadow catch surface (where I project the plate onto) and the imagePlane when setting up lighting in Maya. I guess this is also the reason Rich set up a pre and post render mel script to turn the imagePlane off and back on so he doesn't have to see the ugly edge.

[vlado]

It would be better to use screen-mapped background for this rather than the image plane - e.g. put the File node into the V-Ray background override and set the mode to "Screen" for the V-Ray environment placement node. Recent builds are capable of showing the background in the Maya viewports.

Best regards,
Vlado

[RobPhoboS]

Hi Jason,

Did you get this working correctly in the end ?
I'm just about to do this myself and it's had me confused for a while. In fact I'd really, really, really like to see a video on their youtube channel demonstrating this as surely everyone doing live action + cg needs to know how to do this.
I like to have the instant feedback in the viewport, then sure later composite correctly later.

[jasonhuang1115]

Hi Jason,

Did you get this working correctly in the end ?
I'm just about to do this myself and it's had me confused for a while. In fact I'd really, really, really like to see a video on their youtube channel demonstrating this as surely everyone doing live action + cg needs to know how to do this.
I like to have the instant feedback in the viewport, then sure later composite correctly later.

IIRC, I got it to work as expected following Vlado's last comment. That said, it was months ago for a quick delivery so I am not 100% positive. There are several sample scenes setup posted by Vlado and other devs here. I downloaded all of them and explored the setup. Pretty helpful. Still, a video demonstration would be great.

[RobPhoboS]

IIRC, I got it to work as expected following Vlado's last comment. That said, it was months ago for a quick delivery so I am not 100% positive. There are several sample scenes setup posted by Vlado and other devs here. I downloaded all of them and explored the setup. Pretty helpful. Still, a video demonstration would be great.

Hmm, I've gotten badly sidetracked trying to figure out some matchmoving issue, so I'll get back on this when I can.
If you get a chance to look back through anything that would be useful but as you mentioned there are a few files here and there which are meant to show it working correctly. I think I just had issues trying to replicate as I didn't understand where certain things went etc.

[RobPhoboS]

Right I think I can at least see what's causing my issue here.
I'm using the dome light, when it's on the 'matte' ground is bright, when it's switched off the ground act's exactly as it should be, in my case catching shadows/reflections (although something looks wrong with the colourspace).
So what do you do if you want to use the dome light ?

This included scene is just a quick planky one, the HDR's are from www.hdrlabs.com which are available for free etc

http://www.sendspace.com/file/tgq4l4
(if there is a better site to upload to please let me know, seems ok)

Now typically my background would be video footage, so it would be set to 'screen' as Vlado suggested.
However, I'd want the refl/refra and lighting to come from my HDR.

Of course I would not be rendering out my final CG, pre-composited as I'm looking at it in the VFB. So I would typically have the background footage invisible and only the CG viewable in the rendered sequences, and composite later.
(typical workflow)

[RobPhoboS]

Did anyone get a chance to look at my file ?

[bigbossfr]

I will try. Wait.