PFtrack : Merge Camera solve and geometry track

[joncky]

Hello everyone,

I am new to PFtrack, but I have a question about merging a camera movement and a object movement.

Example :
I would like to have some smoke on a guy's face, the smoke is born on the face (geometry track) but has the drag of the environment (camera track).

The 2 trackings are essentials, is there an easy way to merge the camera solve and the geometry track together in PFtrack?

any ideas are more than welcome !

thanks a lot!

John

[kyrgr]

I did not understand how should the smoke behave-
follow the face or the camera and is it cg?

[joncky]

Hi,

Thanks for the interest!

The smoke was only as an example but,

imagine filming a guy walking from left to right, and the camera follows the guy. ( the face is then always in the center of the frame)
We would add some CG Smoke on his head (it is the emitter) but as he walks it leaves a trail of smoke behind him. ( in the frame : the smoke begins in the middle and goes to the left of the frame)

So I need the geometry track to have the smoke emitter stick to the head.
AND I also need a camera tracking or else the smoke would not leave any trail and would stay around the head.

So how is it possible to have a geometry track and a camera track in the same scene?
In the 3D scene the environment should be static, the head should move as the guy walks (several meters ), and the camera should pan from left to right.


I hope my question is clear enough, Its hard to try to make myself understandable ;-) !

Thanks a lot.

John

[JoshBrokenbourgh]

With minimal parallax it may be tedious solve. Since the camera follows your talent there is little information to track but it should be possible.

You may want to get some more information to help with prepping for the solve:

How long is the scene?

Is the camera on a tripod or hand held etc?

Do you know specific details about the camera - lens, sensor dimensions, distance from the talent, height from the ground etc.

Are there other objects in the scene or are you working with key (are you masking out objects?- if it is not a key).

What are the best areas on the talent to track from (collar, hat, exposed neck etc)

Once you are able to gather this information and get the cleanest track before you solve your camera you should be able to get it. After you get that yes you can export camera data combined with your point cloud into a variety of programs. I've used c4d and ae. Maya, 3dmax etc are other options.When you export the point cloud it sets all the points as null objects. The camera should move just like the shot you track within your application. Where are you taking the data to - where are you generating smoke?

I hope this helps,

J

[kyrgr]

Look i'm no matchmover and no CG artist either. I know that you
can track as many geometries as you want in PFtrack in tracking-
groups-motion(set the number)and new. The emitter follows
the head that's easy. In your 3d app everything you create
follows the camera-in this case the trail( goes with the cam )
You can track inbetween geometry using other motion
group in PFtrack.
Does that help to setup your particles? (don't know which
software you use for that).

[friendly_taha]

well friend,
i dont knw weather u hv xplored it till now or not.... bt in pftrack u cn do scene tracking n geometry tracking together, one after another in the same file....
follow the steps:
1.) first do ur scene tracking scene tracking....
2.)thn, do geometry tracking,
go to file-> "import tracking geometry"

before importing tracking geometry, u shld create new group frm the "tracking" menubar. type the no. of motion "2" ovr der. u ll get the new group, rename it. and close it.
select that newly created group frm under the 'Groups"(left side). and then import tracking geometry frm 'file' menubar.
select the imported geometry from the group under 'tracking Geometry'. n adjust it according to scene with -translate,rotate,scale. n thn u cn do ur geo tracking

well after tracking u cn scale the geometry only by selecting the group which u hv newly created.
and while exporting make sure this newly created group is selected, which contains ur tracking geo


well i hope this will help.... sorry i cldnt write in proper way since i am in hurry.

[darsha]

I don't know what version of pftrack you're using but in 2011 you can have different track groups: one for the head and one for the camera. I'd start with solving the camera and putting it in it's own group, then just hang a object solver to that and select the head tracker group. the nodal based workflow in the new pftrack is just amazing.

[JoshBrokenbourgh]

Wow, just looked up the new pftrack... Looks great! It's great to see the node workflow!

[nidhi_agarwal]

welll i have never worked on pf track... but in maya or anyother 3d software if u want ur object track to go along with ur camera track then the best way is snap ur object tracked camera onto camera track camera.... and then contraint ur whole object track with camera tracked camera... it always works if u do it the right way....

[kyrgr]

I'm pretty sure you can track geometry without solving the camera.
With one correction: create one motion group to track your emitter
with the head and a second to track the last end of the trail with
a background feature not too far -ideally exactly in the characters
z-depth.
Later edit: Is there a way to export the tracked geometry as fbx
to Nuke? For 3d apps i use lws but neither that nor
the Nuke script format seems to be working for Nukex 6.0

[joncky]

Wow! thanks a lot for all those reply.

I am gonna check all of this give you a feedback right away!