compositing and alpha pass in beta 2.2 Tweet

[kubo]

Well, even thou the job is finished, I didn't thought it was worth of the gallery forum, not much "work" into it, since it was a pro-bono job for a relative and I did't have more than two days for completion. The only reason I'm posting it is because of the work flow with the alpha /material passes.
Here is the thing, I had to place this model in the pictures, the pictures were given to me "as is", so I couldn't get extra shots or try to do enviroment or hdri, so after doing some photometry and getting the cameras and a few objects to get reflections and shadows right I was still in need of an alpha and material map to filter just my model plus shadows and fit it in the original pictures. If I did it in the modeling soft I wouldn't match the shadows or dof, so it had to be done in Octane. Well, after a little trial an error I came with a smooth workaround.
I had to suites of files per camera, one with the correct materials applied and another one with a plain difusse totally white material applied to the objects I wanted to filter out, and an all black diffuse to the ones I kept, also an extra all black with opacity for a material that had opacity. I overexposed the hdri enviroment, and had a nice black and white alpha map that matched perfectly my back plate with the right amount of shadows, I had to play a little with the gamma and power of the hdri to get it right, but it could also be done with a second pass just using all black on model and white background.
Well I hope someone finds this useful.
Thanks to kilaD for his script which simplified the flow max-octane, and of course to Octane Team for such a nice and user friendly app.

[Kevin Sanderson]

Great job and thanks for posting it. Looks very good!

[pedrofelipe]

great stuff! I'll try it right away! shame that the backplate was a bit of sh*** photographed!

[kubo]

Yeap, I know, I'll ask if they can take a couple better ones, and with a sunny day too, or rainy, that would look nice, but right now they didn't have time, also I've asked for a picture of the event which I think is in a month, if I get it I'll post it here, just to compare.
Glad you guys liked it

[face]

Realy nice
I would blur it a little bit more, so that it match the foto, then the illusion would be perfect.

[SurfingAlien]

very smart trick, thanks for sharing!

there's a little problem with vanishing point in Z direction, but looks very good

[kubo]

I would blur it a little bit more, so that it match the foto, then the illusion would be perfect.

yeah, I know I should have (also I should have added artifacts), but it pissed me off to deface the render just because the original picture was crap... hehehe....

[face]

I would blur it a little bit more, so that it match the foto, then the illusion would be perfect.

yeah, I know I should have (also I should have added artifacts), but it pissed me off to deface the render just because the original picture was crap... hehehe....

A good reason

[Tugpsx]

Very nice job. Thanks for sharing settings.
The chairs appear to be floating though.
If you still have the project, and i'm sure you do
run an ambient occulusion pass, and use it as a multiplier in photoshop or Gimp. This will give more dept to the darker areas.
A shadow pass would be nice but thats a bit harder to pull off in octane. you could however use the clay mode to simulate an occlusion pass.
Keep up the great work.

[radiance]

awesome work
if i look at the final image i would'nt have been able to figure out it was a composition/render

Radiance