Flow - Projection Rigid Placement Issue

 From:  Michael Gibson
4668.2 In reply to 4668.1 
Hi Mike - the "projective" version of flow works by actually sending out rays from the base plane and intersecting that ray with the target object.

That whole process doesn't really work very well if the target object curves away close to a 90 degree angle from the projection plane - you generally will need to avoid using projective mode if it would require that kind of really steep angle to project on to.

It's more for projecting your object on to a localized area of the target object, so it's more intended that the base plane should normally be smaller than the target object instead of such a large one like you've got here.

See here for an example:

Then the other thing situation that you've got there that causes additional difficulty is that many of the rays that are coming out from the plane like near the corners of the plane are going to completely miss the target object instead of landing on it. It kind of tries to deal with that but both missed rays as well as steep angled rays will tend to make a kind of lumpy projection in those areas - you can actually probably have those kinds of things just as long as you don't also have objects being deformed right in the same neighboring area of the missed rays or steep angle spots which you do have in your case here.

For this case I'd suggest preparing a projection target that's a little different in shape from the actual head - well the inside portion would be the same shape but you want something that's larger and has a kind of "easing off" boundary instead of the true steep boundary, something like this:

The center part of that larger one can be the same profile as your real head, but cut it off where it comes to around 30 degrees of vertical and then make an eased out extension from there. Then you still will project on to the central area only but I think you'll get better behavior, let me know if that helps.

- Michael