Shrinkwrap applied to curve is broken in 2.5?

Hi All,

I was messing around with using shrinkwrap to reveal objects again.

I ran into this demo file I presented as a bug to the developers. They insisted with a quite lengthy multiple reply that what I was experiencing was the intended output of the shrinkwrap modifier working correctly.

What I visually present to you is the shrinkwrap modifier producing garbage on the projected plane.

My argument was that it works correctly for the mesh, but not for the curve. So this must be a bug in the curve processing part of the modifier.

What do you think?

Attachments

25_skrinkwrap_curve_reveal_bug.blend (68.7 KB)


As far as I can see it is doing exactly what you are asking it to do. It is projecting along the Y axis, with the curve it projects all the points to the right of the plane so you get a squashed look. The same thing happens with the mesh object but you don’t see any impact because the object is perfectly horizontal. In this case the order of the modifiers is important, you are shrinkwrapping and then curving, reverse these and you will see the same effect as you will be shrinkwrapping a non horizontal object.

I guess the “spillage” is the problem. When I click Cull Faces for the curve, it does not work. The culled faces spill out on to the projection plane. They should be culled and not drawn in the viewport or rendered. Like the mesh object.

Switch the two modifiers for the mesh object and you’ll see the same effect with the mesh as you see with the curve.

I’d rather just make the curve straight, like the mesh. When I do this it still does not work. But oddly enough, there is a curve modifier for curves. I tried putting a curve modifier on the curve itself and that helped a bit, but I still can not get rid of all the spillage.

I am just looking for a way to do automatic reveals of objects (mesh or extruded curves) in a uniform fashion.

could you use the camera limit?

[quote]could you use the camera limit?


Maybe for a single object, but what about multiple objects and objects that I want to reveal toward the camera?

I just need to schedule some time on the C4D machine. Cinema4D can do this <i>quite easily</i>. I try to do as much work in Blender as possible, but this is just one of those areas where Blender falls behind on what is current with motion graphics.

could you use the camera limit?

Maybe for a single object, but what about multiple objects and objects that I want to reveal toward the camera?

I just need to schedule some time on the C4D machine. Cinema4D can do this quite easily. I try to do as much work in Blender as possible, but this is just one of those areas where Blender falls behind on what is current with motion graphics.

I suppose the most straightforward way in blender to animate one curve being extruded following another curve would be to use a curve modifier and keyframe the scale value for the extruded curve. You can then use complex curve guides unlike the shrinkwrap method. You can use this method for extruding either a curve or mesh object.
http://www.screencast.com/users/blenderwho/folders/Jing/media/1775003a-0967-444b-97b3-da92ad4b0947
http://www.screencast.com/users/blenderwho/folders/Jing/media/4725c2b1-3fbb-425f-b355-6e35b524dd3a

Attachments

pipe_anim.blend (515 KB)meshtube_anim.blend (515 KB)