Using projection node with vray

V-Ray V-Ray for Maya Issues
1

Hi,
I’m using a file projection texture to make camera projection and everything looks correct when using Maya software render , and even mental ray, but when a use v-ray i get a position and size shift, and its related to the output size of the render( and its should be independent )

I’m i doing something wrong or is it a bug?

Scene

Shader network

Vray render

Maya render

Screen Shot 2013-11-27 at 5.48.44 PM.png
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Screen Shot 2013-11-27 at 5.53.45 PM.png
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Screen Shot 2013-11-27 at 5.53.56 PM.jpg
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Screen Shot 2013-11-27 at 5.54.07 PM.png
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2

Hi Joao,
What VRay version are you using?

3

Hi Jao,

you can also use the Vray Place Env Tex node plug that to your image. Then use the screen mode.
That does the same as you trying to achieve.
You can also plug your image in the background, this create the Vray Place Env Tex node and use the screen mode again.

Yannick

4

I’m using 2.30.02.

Thanks

5

Got it to works in this way, with the help of Yannick

Thanks

Screen Shot 2013-11-28 at 11.09.50 AM.png
Screen Shot 2013-11-28 at 11.09.50 AM.png779×394 26.9 KB

6

I still would like to use the maya projection node in v-ray, is that possible?
Mainly because i would like to use different cameras as uv coordinates for maps.

Thanks

7

Sorry for the late reply. This should be working in VRay. I’m not sure if there were some improvements to the camera projections that we added later.
Can we take a look at your scene? I’m interested in seeing your settings for camera/placement nodes/projection nodes.

8

I use projections like that all the time, without any issues. What strikes me is that you don’t seem to have a camera hooked up to the projection node, judging by your first screenshot. Try setting the projection type to “perspective” and then link a camera to the projection node (if you haven’t already).

9

By default the camera projection with the Maya texture projection, works for me. But as soon as you plan with Film offset, overscan… that when it stops working properly for me.

Yannick

10

If you’re just using film offset you can compensate by adjusting the U and V offsets of the 2d placement node attached to whatever you are projecting.
You can work out the value needed by finding the film offset in each axis as a percentage of the camera aperture dimensions (both are measured in the same unit, inches I think, by default)

Eliott

11

Do you know if Maya software or Mental Ray render the image correctly in this case?
If they do we then have a bug, which we should fix.

12

Sending

you can check by just changing render engine to see the difference .

Thanks
projection_error.zip (94.6 KB)

13

it works ok in maya render and in mental ray

14

I’m using this way .

Screen Shot 2013-11-29 at 9.38.17 AM.png
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15

Hi Joao,

Thanks for the scene, I got to look at it. This is actually a bug and we have fixed it for 2.4, which you can download from our website. The fix is also available in the nightly builds. The problem was that VRay wouldn’t render correctly when the projection fit type was set to “Match camera film gate”.

16

Cool good to know.

Cheers.

17

Thanks! By the way, where can i download the nightly builds ?

18

You can contact our support@chaosgroup.com to arrange access to the nightly builds.

19

found this old thread - seems still to be an issue.
projection does work fine in maya software render, but there is a wrong scaling in vray

Capture6.jpg
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20

Not sure if any of the options for fitting the projection need to be tweaked or something else. Can you share a scene ?