When I render two objects with z-depth and composite them with a z-composite, they work properly (one object goes behind the other one), but there's an outline of the background object visible on the foreground one. What is it and how do I get rid of it? Thanks,
Luka

Lukich
When I render two objects with z-depth and composite them with a z-composite, they work properly (one object goes behind the other one), but there's an outline of the background object visible on the foreground one. What is it and how do I get rid of it? Thanks,
Luka

1. Change/apply pixel filter and/or sample filter for a zdepth plate.
2. Use mask-processing tools like a dilate erode, edge detect, edge blur etc.

3. Avoid using Z-depth compositions. They work well only for a distanced object - if they are small on screen. If not, artefacts scare!

This in not a Houdini's specific issue… quite common around.

cheers,
sy.

Yeah, one of the more common first mistakes is the pixel filter you generated it with, ‘minmax min’ is the one you want. After that, yes, depth compositing looks great on paper but in real world examples you will run into a *lot* of problems. If you have motion blur(as virtually every job does nowadays), be prepared for migraines. Motion blur and depth mapping just don't go together.

Having said that, you *can* work around them in many cases, but it ain't pretty, the last job I did that way I had to make about 40 animated garbage mattes to break out layers that didn't play well with the surrounding backgrounds. You can play with different compositing operations such as screen or add instead of overs to get the effect you want, along with other edge erosion techniques as Symek says, but as a rule unless you are in a panic, rendering DOF is usually preferable to depth compositing in any reasonably complicated job.

And yup, this is unrelated to Houdini, it's related to the technology.

Cheers,

J.C.

Thanks, SYmek!!!

Lukich
Thanks, SYmek!!!

Thanks JColdrick!

Ye, I forgot about a different composition modes. They can be helpful in case of masks problems.

Specially mixing masks based on editable curves method (don't remember it's name in Shake but its an AddMix in Nuke) which is apparently missing in Halo… :shock: