Advanced 3d match moving question. at DVinfo.net

Brandon Savoie · February 21st, 2009, 11:19 PM

I have a question about 3d match moving. I understand the basics of it, such as tracking points and 3d cameras, but I am kind of confused about how I should set up a particular shot. This particular shot requires the actor to actually hold the 3d object in his hand, so I am wondering if anyone knows the best approach to setting up this shot. The shot will consist of the actor standing in front of a green screen. He will be "holding" the 3d object, which will be a small toy, and he will raise it up to his face. I am unsure of the best approach to this because the only tracking I've done so far are shots where the 3d objects are on the ground or some other stationary object, such as a table. I was thinking the actor could actually hold a real object whose shape resembles the 3d model, and then it could be replaced in post. Is that a good idea? Have any advice?

Eric Lagerlof · February 27th, 2009, 10:20 AM

How about this: On the shoot put something of similar shape in his hand with a couple of pasted-on tracking dots, so AE can see where it is moving and how the hand is tilting it as it moves. (Just make sure the 'stand-in' is smaller than your 3d object.)

Bring footage into AE, add 3d object- properly sized- in layer above and then add footage layer again, above the other two layers. Mask the top footage layer to show only the talents' hand that shows in front of virtual object. Motion analyze the 'stand-in' object's dots from bottom layer and apply motion info to the top two layers. Should work, I think.

February 21st, 2009, 11:19 PM	#1
Brandon Savoie Regular Crew Join Date: Jun 2006 Location: New Orleans, Louisiana Posts: 28	Advanced 3d match moving question. I have a question about 3d match moving. I understand the basics of it, such as tracking points and 3d cameras, but I am kind of confused about how I should set up a particular shot. This particular shot requires the actor to actually hold the 3d object in his hand, so I am wondering if anyone knows the best approach to setting up this shot. The shot will consist of the actor standing in front of a green screen. He will be "holding" the 3d object, which will be a small toy, and he will raise it up to his face. I am unsure of the best approach to this because the only tracking I've done so far are shots where the 3d objects are on the ground or some other stationary object, such as a table. I was thinking the actor could actually hold a real object whose shape resembles the 3d model, and then it could be replaced in post. Is that a good idea? Have any advice?

February 27th, 2009, 10:20 AM	#2
Eric Lagerlof Major Player Join Date: Mar 2004 Location: Pacifica, CA Posts: 348	How about this: On the shoot put something of similar shape in his hand with a couple of pasted-on tracking dots, so AE can see where it is moving and how the hand is tilting it as it moves. (Just make sure the 'stand-in' is smaller than your 3d object.) Bring footage into AE, add 3d object- properly sized- in layer above and then add footage layer again, above the other two layers. Mask the top footage layer to show only the talents' hand that shows in front of virtual object. Motion analyze the 'stand-in' object's dots from bottom layer and apply motion info to the top two layers. Should work, I think.