How to render a car on top of a background image

6.Now open the materials rollout or press “M” and make a new VRay material. Now on the same material select a new VRayMtlWrapper and when it asks you if you want to keep the old material as a sub material click OK. Now check the Matte Surface and Shadow boxes like on the following picture:

7.Here comes the tricky part. For a good CG image you have to make sure that your object is properly aligned to the background image. To do it, you have to find some reference points on your background image which you could use as guidelines. In my case I use the bottom and the top of the staircase and the lane across the street (marked with red). What I did was to rotate my camera angle , not the plane to match the perspective and orientation of the staircase lines (marked with green). After you have matched you angle press “CTRL C” to make a camera at that spot so you don’t accidentally move your viewport.

8. Here we are going to load our HDRI image. To do so open the materials menu and click on “Get material” button, then scroll down until you find the VRay HDRI map and select it. From there you can browse your HDRI image. Make sure that the Mapping type is set to Spherical. You can also play with overall multiplier as well to get better results. After you are done with that open the render dialogue and go to VRay environment and drag your HDRI to the GI Environment and Reflection/Refraction slots.

9. By now you should have something like that:

10.And we are done. But not quite yet. If you are using a HDRI and Backplate form one package like I do (the background is matching the HDRI) we have to make sure that the HDRI image is well orientated to our background image. To do so make a simple sphere where your object will be and assign a chrome material to it. The render. What I had is this:

As you can see the red building is being reflected on the balls face which is facing us, but the building is behind the ball so that is WRONG. To fix this open again the materials rollout and rotate the HDRI map by several degrees Horizontaly (I did 180 degrees) until I got the red building reflections behind the ball:

In this step you may have to experiment a few times until you set the HDRI right, but it will be wrong to reflect something that is behind you.

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9 Comments on "How to render a car on top of a background image"

  • mohit

    dear brother how u put soft shadow in the scene. r these with the help of vray sun or some other light. please help on mohitarnold@gmail.com

    regards

    • ludwig770

      Use a Vray sun, and turn the size multiplier up in the modify bar. The higher the size, the softer the shadow….

  • mxr7

    this site is amazing!!!!! love it :)

  • Alberto

    Gracias por el tut, bien contado, claro y muy util…un abrazo desde Argentina.

  • nitin pasbola

    perfect….. i try it on my homes image

  • Thank you very much!

  • BENNY BANASA

    Hi I’m a beginner on Vray. what material should I use for the car.
    Thanks

  • leonardo

    Hi,
    Do you have the same type of tutorial for MAYA, I tried to follow this tutorial, but the properties boxes are all different and I couldnt find some of the most important ones… like the “see-through” checkbox on the shadow plane !!

    Help!!.;..lol

  • brock

    Great
    thanks