Tuesday, 8 November 2011

Camera Projection

Yesterday was supposed to be the day when this shot came together, it was supposed to be a shinning moment, and then the track didn't work and blew my whole operation. I ended up doing a blog entry about reflections and shadows and some other hot air to try and cover up the fact my track didn't work.

Well, today, even though I'm ashamed of it I'm going to post the track that looks like arse, but I'm also going to post a little bit about camera projection, which in this case has been a bit of a get out of jail free card.

As I said in my last post, there was a number of benefits in recreating the physical environment within Maya, accurate lighting and shadows to name a few, but the ability to generate a believable camera projection in place of texturing every surface is another.

This image that I'm reusing again because I'm to lazy to render another shot out show's the camera projection at work. In my last post I spoke about how camera projection works to generate reflections onto the ball, this time however I am using the projection to actually texture the geometry.

This Maya view window animation gives a graphic representation of the geometry, the renderable camera and the projection camera.

This is my track that unfortunately didn't work out, which is always a shame. In this particular render, I hid the virtual geometry and just rendered out the ball with it's reflections (last blog entry) and then added the actual footage back in at the comp stage. This helped cut down render times although as you can see. Because the ball  movement didn't match the footage it looks horrible and there is next to nothing that can be done to fix it apart from retracking the footage.

So, what I decided to do was re-render the scene, only this time I would only render the virtual environment with 1 single frame of the footage projected onto it. This image to be precise:

As the original footage now appears nowhere in these sequence there can be no conflict between track and footage. The following shot is the virtual geometry with the one singe frame being projected into it by a locked off projection camera and the match-moved camera moving through the scene.

As you can see there are a few anomalies towards the end as the renderable camera moves out of the range of the projected frame, although if I had the inclination to fix it, this could be rectified with multiple projection cameras throughout the scene stitching together the whole footage from 4 or 5 frames. Also notice that the ball now fits perfectly in the sequence with no slippage at all due to there being no original footage, it is 100% virtual.

All in all I'm pretty impressed with the way it came out and it just goes to show that even when things fuck up badly, there's still a positive to come out of it!

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