Holding objects in place in 3d Space

[Walter Soyka]

You could make the objects 2D, or maybe parent them to the camera (so they move with the camera).

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
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[Gerald Hapeman]

Well… when I place the object layers as 2d… they slide all over the place much worse than in 3d. Parenting them to the camera doesn’t work because I’m winding through the scene and panning above, so the elements appear to move, slide across as I move the camera. Thanks for your reply though. I’ll keep trying – I guess it may be just about where the camera is — I was hoping there was some method to hold things in place.

[Walter Soyka]

[Gerald Hapeman] “Well… when I place the object layers as 2d… they slide all over the place much worse than in 3d.”

Let’s solve this problem the right way. If your 3D objects are sliding when the camera moves, then they are not positioned correctly.

It’s practically impossible to eyeball the the correct placement of a 3D object in a scene through the active camera only. Switch AE’s comp viewer from 1 View to 4 Views and observe the location of the objects from the top, front, and left or right as well as the active camera as you put them in place.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
Creative Cow Forum Host: Live & Stage Events

[Gerald Hapeman]

Thank you — I’ve done the 2view only, so perhaps the 4view is of better help. Maybe they are ‘hanging’ in space and all I need to do is readjust. THANKS… On to it…!

[Darby Edelen]

More triage might be helpful in this case.

Are you trying to match a 3D camera move to footage, that is to say: is this a camera tracking question? It doesn’t sound like it from your description of animating the camera, but if it is then it sounds like the track is bad.

Do the 3D layers appear to be sliding relative to other 3D layers? If that’s the case then I highly recommend placing layers relative to one another by creating Parent/Child relationships.

When you make a layer a child of another layer it’s coordinates are relative to the parent layer’s transformations. This makes it very easy to, for example, place footage of a person (child layer) onto a floor (parent layer).

Another problem you might be facing is perspective present in the footage items you are using. Most footage of people, for example, is not shot so that their feet are “flat” on the ground. If you move your virtual camera too far from the actual perspective of the recorded image, then the perspective mismatch will most likely be evident.

If none of this helps then I’d suggest posting a few pictures or a render of the problem.

Darby Edelen

[Gerald Hapeman]

Thank you Darby — Perspective was one problem. Motioning my camera (weaving through people) and adjusting it so they didn’t appear as the grass was suddenly a hockey rink was a major do over and over and over again! But I was looking for a simplistic answer and I think you’ve given it to me. Parenting. So obvious that it’s painful to hear… I’ll parent the people to the ground and see what gives… Hopefully, nothing!

(should have known that. My other people layers are tethered to the hills and ground by what I created in PS, but the added figures weren’t and I couldn’t figure out how to stop the sliding nightmare. I’ll give her a go –)

Many thanks!