Nic-Gun

hello guys, i need some help here..

any body know how i can access the pivot point in a 3d object my friend said that the pivot point is set when the object is created using 3d modelers such as 3dsmax or lightwave.

the thing is that i want to do a circular movement on a 3d object (obj A) based on other 3d object's (obj B) rotation and using xna, i can only rotate obj A with it's own pivot point.

hope i'm not confusing everyone with my explanations.



Re: XNA Framework accessing pivot point in 3d objects

waruwaru

Is object A a moon, and you want it to orbit around object B If you are already rotate A around its own center, then you are half way there! Just move/transpoe object A in a circle around B as you rotate A, then it will look like it's orbitting around B. Hope that answers your question.




Re: XNA Framework accessing pivot point in 3d objects

Nic-Gun

well the obj A is a robot/mecha and the obj B is an asteroid. i want to make the robot able to grab the asteroid and when it does, it will move around with the asteroid. and since the asteroid is rotating around, i want to make the robot rotate as well with the asteroid. yeah you can say its like orbiting the asteroid.

if that's the easiest way to do it then i'll try it out. but if there are other ways as well, please let me know too. thanks.






Re: XNA Framework accessing pivot point in 3d objects

selinux.es

Hi

I'm using maya models exported to fbx files. I set the pivot point of the model anywhere. For example, in a ball, the pivot point is the sphere's center. In a vehicle, I put the pivot near the floor.

The pivot point isn't an element of the model.

When I import the fbx into xna, always, the pivot point is the relative center of the object (0,0,0). Al vertices of the model are relative to the pivot point.





Re: XNA Framework accessing pivot point in 3d objects

Daniel Gadens

If you modify the world transformation

scale * rotations * tranlation

to

scale * translation * rotation

with this you change the point of rotation

:)