3D Camera Tracker to Compositing

Support Compositing and Post Processing
1

I need a bit of help figuring out the best way to composite a scene after using the 3D camera tracker. I’ve got drone footage of a house, and I decided it would be good practice to see if I could put a CG hole in the roof.

Image1: Pixel error of 0.57 after refining. I’m happy with that.

blender 2018-01-26 13-56-05-20.jpg1920×1028 857 KB

Image 2: Example object added onto roof.

blender 2018-01-26 13-57-50-96.jpg1920×1028 448 KB

Before I get to making the hole, I wanted to figure out a few problems I had while doing test renders. Any help or advice is greatly appreciated.

  1. After pressing the “Set up Tracking Scene” button, the 3D viewport uses the original video as a background image from the camera’s perspective. This background image is used when I render the animation. How would I disable this background, so I am only left with the CG elements? My intention is to import into After Effects to composite since I havn’t learned Blender’s compositor yet.

  2. I imported a fully textured bucket model I made, and put it in place of the cube you see in image 2. The bucket appeared partially transparent at render, as I could see the shingles of the roof through the model. Any idea what causes this? It doesn’t seem to happen with a basic cube.

  3. I refined the tracking using the “Focal length, K1” option because this seemed to lower the average pixel error by the most. Now that the K1 value is changed, the clip appears distorted from the original. If I were to render only the CG elements, I would have trouble adding them on top of the original footage, since the original would not have this distortion. Any ideas? Am I approaching this wrong?

2

I would recommend learning blenders compositor. It has a distort/undistort node that will perfectly sync with the camera distortion. You’ll also find the background scene that was setup by the auto button in the compositing nodes.

Not sure about the transparent bucket, but I bet it’s also something in the compositor. Even if you do your final composite in AE, getting familiar with some of the tools available in blender will only help you out.

3

Ya probably not a bad idea. Any good sources for learning the compsitor?

4

I usually just ask Google, myself. On the blender cloud, the track match blend tutorial is pretty good.

5

I could maybe recommend www.openvisualfx.com :wink:

6

Make sure you add the bucket to the same layer the cube is on, and not the layer the plane is on.

7

Thanks, I’ll look into that.

8

Hey what do you know, that fixed it! :smiley: I dunno why I didn’t think of that. I guess it was treating the bucket like a shadow or something.