simply overlapping objects

[farshizzo]

You will need to use some 3D math to determine the orientation of the triangle. Here is some code that will return the transormation matrix of a triangle, given 3 points:

import viz
viz.go()


P1 = [-1,1,2]
P2 = [-0.1,2,2.5]
P3 = [1,0.1,2.3]


def GetTriangleMatrix(p1,p2,p3):
	
	#Get vector of p1 to p2
	v1 = viz.Vector(p2) - viz.Vector(p1)
	
	#Get vector of p1 to p3
	v2 = viz.Vector(p3) - viz.Vector(p1)
	
	#Take cross product to determine normal of triangle
	normal = v2 ^ v1
	
	#Determine rotation by rotating forward vector to normal
	m = viz.Matrix()
	m.makeVecRotVec([0,0,1],normal)
	
	#Set position of matrix to center of triangle
	p = viz.Vector(p1) + viz.Vector(p2) + viz.Vector(p3)
	m.setPosition( p / 3.0 )
	
	#Return the transformation matrix
	return m
	
	
#Draw triangle
viz.startlayer(viz.TRIANGLES)
viz.vertexcolor(viz.RED)
viz.vertex(P1)
viz.vertex(P2)
viz.vertex(P3)
viz.endlayer()

#Get matrix of triangle
m = GetTriangleMatrix(P1,P2,P3)

#Create arrow to show triangle rotation/translation
arrow = viz.add('marker.wrl')
arrow.setMatrix(m)

#Setup pivot camera
import vizcam
vizcam.PivotNavigate(center=m.getPosition(),distance=10)

#Add ground
viz.add('tut_ground.wrl')

[chris]

Wow that's exactly what I needed thanks!

I also didn't know about ^, that makes life a bit easier.

However this brings up another issue.

While my actual project is a bit more complex then the example I asked for, the solution transfered to it extremely well. The issue now is I'm applying this transformation matrix to an on the fly object, which in itself works, however the transformation is applied at the objects current center, which geometrically is not its center at all. All attempts at object.center have failed.

I was wondering if there was a simple solution for this one.

[farshizzo]

The best solution is to create the triangles so their geometric center corresponds to the origin (0,0,0). Is this not a viable option for you?