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: https://www.photopea.com/
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
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?
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.
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).
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.
The exact location of a matched photo doesn’t translate into the camera systems that renderers use - you have to move it just a fraction to get it to work - (which does throw it off a little)
How I’ve done this kind of thing in the past is to do the match photo - then project this onto some basic planes - floor and walls
Once you’ve done this you’ve got textures that are perspective correct and a little 3D world in which to work in. If you’ve really nailed the original photo match you will find you can reposition the camera an things will look ok.
One advantage to doing it this way is that your objects will gain their own shadows or be reflected in the surfaces that you have made (I’ve made the floor texture shiny for example, so the object and scale figure from sketchup are actually reflected in my “photo”)
Once you’ve got a decent result, you can then auto-align it with the original photo and paint in any lost detail etc.
Thanks for the tips mate. I managed to get the rendering to match the photo using by ensuring the render output settings matched the size of the original photo, and the zoom level of model in SketchUp correct as per the original photo match - i.e. clicking on the tab for that view before starting the render. Thanks as well for the tips about shadows and working on “modelled” components. That makes a lot of sense.
