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Br0nZiLLa
03-27-2003, 06:31 PM
Ive tracked my camera (boujou) then exported it into maya..now my question is..how how i know how big my geometry should be in the scene? So it is al in proportion with the live action? How can you test that? And does someone has some other good tips here..?
thanks!:wavey:

LarsSon
03-29-2003, 02:09 PM
Describe scene geometry.
If i remember right, there is that kind of option. There you can describe your real world geometry to match your 3d scene. You could also give right xyz axis to your track from there.

Hope you have some measurements from your video footage, helps alot.

Dazza
03-29-2003, 07:55 PM
Yep,

I had the same probs with my cg dragon,going through a forest scene, I set it up ok and steadycamed the whole thing,no probs,so i brought it in to bjou and it track with no probs what so ever,the objects stayed locked down.

The problem came when wanting it to go to maya,the info bjou give on setting up the coordinates so xyz is bizzare,and the geom might end up the right size.(this is Ther problem area).

So bringing the scene into maya ok, but my primatives were just moving around and not locked down.I put this down to the last bit of boujou before export.

To end on this my mate brought the scene into max,and although he had to change his xyz,and input focal length,he said it matched fine,but he said the ball geom needed to be bigger.If i have to,exporting to and from max might be an option.

I dont know if were gonna find tuts or troubleshooters on the net,our best bet is to tell people our solutions as we find them on cg talk.
regards
dazza

Br0nZiLLa
03-30-2003, 09:33 AM
Originally posted by Dazza
Yep,

I had the same probs with my cg dragon,going through a forest scene, I set it up ok and steadycamed the whole thing,no probs,so i brought it in to bjou and it track with no probs what so ever,the objects stayed locked down.

The problem came when wanting it to go to maya,the info bjou give on setting up the coordinates so xyz is bizzare,and the geom might end up the right size.(this is Ther problem area).

So bringing the scene into maya ok, but my primatives were just moving around and not locked down.I put this down to the last bit of boujou before export.

To end on this my mate brought the scene into max,and although he had to change his xyz,and input focal length,he said it matched fine,but he said the ball geom needed to be bigger.If i have to,exporting to and from max might be an option.

I dont know if were gonna find tuts or troubleshooters on the net,our best bet is to tell people our solutions as we find them on cg talk.
regards
dazza thanks mate. what do u mean with XYZ (im a noob)...thanks a bunch!:wavey:

Br0nZiLLa
03-30-2003, 09:34 AM
Originally posted by LarsSon
Describe scene geometry.
If i remember right, there is that kind of option. There you can describe your real world geometry to match your 3d scene. You could also give right xyz axis to your track from there.

Hope you have some measurements from your video footage, helps alot. what do u mean with the right xyz axis?..and measurements from my video footage?
thanks!!:wavey:

Dazza
03-30-2003, 07:44 PM
Sorry,i ment the output to maya from bjou needs z up so the camera does not come into the program on its side,like my mates did in max,but for me it came itnto maya purfect,but the tracking was out of wack,which i think stems from the last part of bjou in describeing the scene detail,i will b going into thisprob 24/7 soon on bjou2 but now im painting my cgdragon.
Will post my results... and i will crack it!

Also u proberly know, those points that u bring in with the scene file,are pointers that u can use ,so when in my forest i can pick my ground plane and bend it to where i can see markers on the ground,so my plane follows the contours of the ground in the live scene.Also parenting null points to polytrees and polystones and poly tree stumps,giving u correct distances so a character or effect can pass around these,and thus give good shadows when u render.

Also to quicken my test up i did a quick garbage matte of my guy running through the forest,this quickend the results and gave the nulls that were moveing and buggering up by tracking him other usefull things to do.
hope some of this info helped
dazza

Dazza
03-30-2003, 07:58 PM
Sorry just a thought about measureing and such.

well bjou just needs good clean footage,i did put in my test about 40 sprayed ping pong balls(red) good colour for a green forest.
and i planted them with blue tack on 3 levels on the ground (stuck to roots etc) on two foot sticks and on differnt trees,just incase.I know im gonna have to comp them all out,but its all part of the fun.

now, bjou actually does a good job of measureing the set for u,and it gives u all the null points to show you where it thinks your real world objects are,and u can see this if u go into the side veiw in maya and look at all the nulls it shows the spaceing ,play it back and u can see in the live footage and the side veiw where u plant your poly/nurbs objects into your scene.

dazza

Br0nZiLLa
04-02-2003, 07:01 AM
oke..this is all kinda new to me so hard to unterstand as of this minute. thanks anyway:surprised :shrug: :wavey:

joconnell
04-02-2003, 10:00 AM
I think what dazza means is that any time you shoot live action footage to be tracked, you normally put a few object into the place you are shooting the footage to help you later on. For example, most camera tracking software works best if you have lots of little points that stand out from the background easily - So if you are shooting a very dark environment, then putting white ping pong balls into the set as tracking points will help quite a bit as the software will have plenty of contrast between the white ping pong ball and the black environment to make a clean track.

The second thing dazza was saying was that it is a good idea to measure certain parts of your set. For example I tracked footage that was filmed in a kitchen set a while ago with a table, chairs and lots of kitchen presses. I measured how high the chair legs, presses and table was from top to bottom. Then when I had my camera track done, I happened to have a null at the base of one of the chair legs and another null at the top. I was able to tell the tracking software that the vertical distance between the two nulls was 3 feet (for example). The tracking software can use this information to make all of the nulls in the scene the proper real life distances apart. Then all I have to do is make a 3d chair leg that is 3 feet high in my 3d software and I have a scale reference for my scene. The nulls that boujou exports will give you clues as to where the base of most objects are so you can tell where a surface starts and stops - use these reference points as much as possible.

I really explained the second part badly there but I've got a flu and can't think - Will re write this later :) - Heres a simple run through tutorial that covers a non moving camera -http://www.rethinkfx.com/tutorials/compmax.htm

Br0nZiLLa
04-08-2003, 08:56 AM
allright..still all kind of hard to understand. But i think i get the hang of it.
Thanks a bunch.
:wavey:

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