How to set matched photo as V-Ray background image?


I’m new in Sketchup and need some help. I have a photo of building in which I need to add fence and make render as composite. I used photo match and by that made 3d model of fence. I know I can export that as image but I would like to make render with V-ray. My questions is how can I make photo matched image as my background, or there is something else I need to do before rendering. Maybe I need to import background as a texture on plane, but then I need to ‘‘fix’’ perspective between model and background plane?


I’d suggest adding the background image in post-processing. You can use a free app like Photopea for that:
That is the closest thing to Photoshop you can get for free.

You can also add a background image in the V-ray Frame Buffer

Thanks for the answer,

but problem is that fence is transparent and I would like to make render that looks like as exported image of composite. Is there a way to adjust perspective of the background image that I put via v-ray frame buffer and 3d model?

Can you show your Photo Match image and render?

Here are the images of photo match and render with background image. As I said, I am new in using Sketchup so probably missing some steps for render.

Are you combining the images in an image editor?

My idea was to make render of the background image and model, than use photoshop to combine images.

OK. So what happens if you put the rendered image on a layer over the background image in Photoshop and set the layer to Multiply? You can also play with the layer’s opacity to fine tune it.

The thing you have to keep in mind is the rendering application isn’t make a transparent image.

The process would be basically the same as what I sometimes do with my renders combining them with line work directly out of SketchUp.

Here I have the line work image. Black lines on white.

And my rendered image.

Copy and paste the line work to a layer over the rendered image that is set to Multiply.

I haven’t done that part yet. My problem is that I can’t make good render with v-ray because when I do, model of the fence tilts as it can be seen on the second image I posted. My question is how can I adjust perspective of the v-ray background and photo matched image so I can get render as it looks like image first image I posted.

There must be a way to set the camera in Vray to match the scene in your SketchUp model. I don’t use Vray but the renderer uses the scenes in the SketchUp file as cameras so making matched images isn’t a problem.

After matching photo select the zoom tool and type exactly the same fov value you are getting. This way you get the same view without background which you can save as a new scene. Obviously you shouldn’t change the camera tilt in vray and compose in post, frame buffer or eventually with a water mark (not sure if this will work).

You imply that you have to adjust the Vray “camera” to match the field of view in SketchUp. Vray doesn’t pick it up from the scene?

No, I meant you shouldn’t do it in vray. There is an option for tilt camera in vray that would distort the view again and the rendering wouldn’t fit.

I didn’t change tilt settings in v-ray. I don’t know but scene changes when I open v-ray asset editor or try to render.

My workflow is creating a new scene without background (the way I said), rendering that one and compositing in ps.
As far as I know, rendering the match photo scene directly is always leading to this problem.
I hope that helps.

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Got this to work. as seen in the photo

  1. Set the Render output pixel Ratio the same as the ratio of the photo

  2. zoom the camera in sketchup to fit the whole photo on the visible screen.