compositing and alpha pass in beta 2.2
Posted: Sun May 16, 2010 12:42 am
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.
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.
