Look at contraint....?!?

[Giovanni]

Hi all,
I just need to have all my billboards to rotate on the Z axis to "look" at the current camera...

Is this doable only with a script?

I just cannot figure out a way to use either "look at" or "orientation" constraints to do this...

It's hard to believe MAX 7 cannot do it natively...

Thankks for your help,

regards,

gio

[Morbid Angel]

Giovanni, look at this scene and let me know if that solves your problem

http://www3.telus.net/public/vinnik8...r_solution.max

[Giovanni]

Hey, thank you, that was cool, but I am not sure I can reverse engineer it...

I see you have created a dummy right under the camera, and then put a look at on the box, right?

Now, could you give me a few points on how you set up the box? That is, you just applied a look at constraint and selected the dummy?

I could not find the settings I normally get when I use the look at constaint (all those X,Y and Z axis settings..)


Thank you

regards

gio

[Morbid Angel]

its really simple:
you create a dummy which you alingn to your camera, the idea is to isolatethe Z path for you camera. Since you cant do it with look at as it will affect all of the channels XYZ, so you have to make sure your dummy is on the same axis as camera XY but the Z axis is the same as Billboards panel. So what you do is create a dummy align to camera, then align it to panel on Z only. Then link the dummy to camera, go to hirarchy panel and in link info unchek inherit transforms on Z so that the dummy moves with the camera on XY but Z remains stady so that your billboard panels dont move on XY. Then you select you billboard panel and go look at contraint to dummy. Then if the panel is offset strangly you check keep initial offset in the motion panel contraint controls, then go affect pivot only and rotate the pivot to match the billboard panels position to your camera....
Give it a try its a bit complex, but its not really that hard.

[DaForce]

Hey good idea MA

[plastic_]

with a scripted controller it works without dummy.
i did it with my tree shop script.
http://plugins.angstraum.at/treeshop/manual.htm
in addition to look-at-camera, there is also a align-to-renderview-at-rendertime callback option.
source code is included.