Cg Arm..

Become a member of the CGSociety

Connect, Share, and Learn with our Large Growing CG Art Community. It's Free!

Thread Tools Search this Thread Display Modes
  10 October 2012
Question Cg Arm..

hello..i need you guys help.. here my friend want to make a cg arm like a terminator but in different type of arm..if you know what i mean..and can you all tell me how to put cg arm in live action footage character..or is there any way to track his arm to input a CG in friend really really need it..please reply ty..
  10 October 2012
I think you might want to let us know what software your friend is using first, so that people familiar with it can help.
I like to learn.
  10 October 2012
There's really only one good way to do this:

1) You need to create a "Terminator arm" that is slightly bigger in size than the live action actor's arm.

2) You need to rig this CG arm for animation

3) You need to bring the live action footage into your 3D software of choice

4) You now need to pose the "CG arm" frame by frame to match the actor's arm, and to cover it completely (so the original arm cannot be seen anymore)

5) Now you need to match the lighting direction of the scene in your CG software

6) After rendering the CG arm, use color correction and other post adjustments to make it blend into the live-action footage as well as possible. It is advisable to use a compositing software for this.

7) If your intention is to replace a larger real arm with a smaller "Terminator Arm", then this becomes much more difficult. You'll have to paint out/rotoscope the real arm in a compositing software, and reconstruct the missing background it was covering frame by frame (this is pretty difficult and time consuming work).

I hope this helps, and good luck with your project...
  10 October 2012
CG arm..

my friend use maya...and here is example i pick in friend wanted more like this... and this ... i hope this video may help on what my friend really wanted to..ty..
  10 October 2012
Both examples you show use a "Difference Matte" (< ---- Google this).

It works like this:

1) The camera is on a tripod and stays completely still during the shot.

2) First the background is shot without an actor in front of it.

3) Now the background is shot with an actor in front of it.

4) Using a "Difference Matte" operation, your compositing software can separate and cut out the actor from the background

5) You can now use "Masking" or "Rotoscoping" tools to remove the arm of the actor, and replace it with the static scene background (the arm becomes "invisible")

This will only work if the arm is extended over the scene background, however. The arm must not cover parts of the actor, like his chest. Otherwise you have an additional job of reconstructing the chest as well as the background. This isn't easy. Unless your actor wears clothing in a distinct, uniform color (e.g. plain red/green/blue t-shirt with no pattern on it).

6) Now you add your 3D CG arm into the scene, animate it, render it, composite and color correct it, et cetera.

I hope this info helps you.
  10 October 2012
CG arm

ty so much Depaint and one last question do you know what is it at her arm.. and is there another way to track an arms.. ty..
  10 October 2012
I don't know what they are using to track the arm in that example.

It could be that the helper points/spheres on her arm are purely there as visual reference for posing the CG arm manually in the 3D software.

It could be that they are using some sort of automated tracker software for the arm.

You could try playing around with SynthEyes a bit:

If I am not mistaken, it has a mode where you can track individual physical objects that are in a scene, rather than the whole scene.

That may give you the "arm-tracking" you are after.

Hope that helps...
  10 October 2012
i use boujou..
  10 October 2012
You have a $10,000 program and don't know how to use it >< ?

Anyway in the VFS short you showed it may have been a form of motion capture for the arms rotations or merely a setup for the animator to use as a reference to get rotation and positions accurate when animating. Tracking an arm and getting it to match takes a lot of expensive software, I am pretty sure boujou is mostly for matching camera movement and not actor movement. Ultimately your best bet would be to manually animate and replace the the arm as previously mentioned. If I were to personally work on the shot I would take that route for the least amount of frustration in dealing with a solver, placing reference objects on the arm as seen in the video you shared would be useful as well to make sure your positions are very accurate and sell the shot better.
  10 October 2012
hahaha.. and yes i have 10k software.. well im new in vfx.. so i need learn more deeply about this thing.. i got discount from my friend i got only 1k..
  10 October 2012
Thread automatically closed

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.
CGTalk Policy/Legalities
Note that as CGTalk Members, you agree to the terms and conditions of using this website.
Thread Closed share thread

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Society of Digital Artists

Powered by vBulletin
Copyright 2000 - 2006,
Jelsoft Enterprises Ltd.
Minimize Ads
Forum Jump

All times are GMT. The time now is 02:20 AM.

Powered by vBulletin
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.