spikes

[ibutter]

i want to attach geometry to the normals of an object. Such as spikes on a ball.... I thought the best way to do this is to paint particles on a surface and instance the geomtery to the particles. But i am having trouble with the direction the objects face (or aim). Instead of facing outward from the object they all aim the same direction, upward or whatever direction the original instance is aiming). is there a way to fix this...or an easier way besides making alot of objects and rotating them to the proper angle.
thanks

ibutter

[fomstudios]

Sure. Create a sphere (default in this example). Create a cone. Scale the cone to your liking for your spike size. Move the cone to the top of the sphere. Snap the cone's pivot to the origin. Select the cone. Go to Edit > Duplicate and set Rotate Z to 45 degrees, number of copies to 7. Hit Apply. You now have eight cones circling around the Z axis. Select the seven duplicates and set the Duplicate options to rotate Y 45 degrees and set Rotate Z back to 0. Hit Apply twice. Done. Hope this helps...

Cheers,
Eric

[ibutter]

thanks....but,
I was trying to emulate houdini's Copy SOP in a fashion. I was hoping to control the placement by painting particles on a surface... a less uniforn method than duplicate.. and then grab the normal information and use that it for the angle of the instance. Then the spike could rotate when the sphere is deformed sticking to the normals angle. I would assume that maya can do it.. maybe a little Mel. In Houdini.. you can copy an object to the points on a surface... and then attach them to the normals angle. Maybe i'm a little spoiled form my houdini days.

ibutter

[heydiddlediddle]

You can use the paintGeometry.mel script. I can't remember if it's installed with Maya, but you can get it either from here or the Alias maya website. I think it might be exactly what you're looking for.

-Don

[satellite]

I can think of two ways to do it. You can use either constraints or motion paths.

Constraints: Use a geometry constraint to make the cone stick to the surface of the sphere. Then, use a normal constraint to make the aim vector align with the normal of the surface. Takes some playing around, but should do what you want.

Motion Paths: Create curves on the sphere by making it live and drawing them, or by projecting curves onto the sphere. Use those curves as path curves for motion paths. If you key it right, you can make the object assume a certain position on the path for all time.

If you also take advantage of grouping the objects to themselves, you can give yourself some extra degrees of freedom to edt.

Hope this helps.

Jeremiah

[ibutter]

thanks.. i just downloaded it.. i'll give it a try and get back to you.

ibutter

[ibutter]

exactly what i was looking for perfect.... after i turned off "group", "align", and jittered the grid in the geometry paint settings, things were working great.
time to break out the wacom board. Any literature detailing this script (paintGeometry.mel) or advise from previous use.

Thanks ... great help.

ibutter