Rotate pivot to Targeted Obj

By JokerMartini · 2012-08-09

Description

How would I create this same script but without the hassle of using the point object and just modifying the actual objects pivot?

I'm trying to rotate a pivot to look in the direction of a target with an axis constraint.

To test just create a bunch of boxes on different position in 3d space and then create a sphere at 0,0,0 using that as the target.

targetObj = $Sphere001 sel = selection as array for obj in sel do ( --pivotLookAt obj $Sphere001 local dummyPt = point()

dist = obj.pos - targetObj.pos
dist = normalize dist
upVec = [0,0,1]
dp = dot dist upVec
t = acos dp
c = cross upVec dist
c = normalize c
dummyPt.transform = obj.transform
dummyPt.dir = c
dummyPt.pos = obj.center
in coordsys local rotate dummyPt (eulerangles -90 0 0)
in coordsys local rotate dummyPt (eulerangles 0 0 -90)

worldAlignPivot obj
theRot = dummyPt.rotation
in coordsys local obj.rotation *= theRot
obj.objectoffsetrot*= theRot
obj.objectoffsetpos*= theRot
delete dummyPt
)

Comments (12)

ashmantills · 2012-09-04

well that is the code that i need thanks for sharing this with us.

dry cleaning epos

Graph · 2012-08-10

no biggie Jack :P

JokerMartini · 2012-08-10

I think this works. I'll let you know how it goes. Thanks for the help Ralph

Graph · 2012-08-10

hey grant, have you tried the code i suplied?
with it you just gotta make sure to set yAxis to the local y of the object to rotate

local yAxis = [0,1,0]*$Teapot007.transform.rotationPart

to wrap it in a method:


(
	fn lookAtFN target others vec:[0,1,0] = 
	(
		for o in others do
		(
			local yAxis = vec*o.transform.rotationPart
			
			local pivPos = o.pos
			local objPos = target.pos
			
			local ang = acos(dot(normalize (objPos-pivPos)) (normalize (yAxis)))
			
			local rot_box = if pivPos.x > objPos.x then eulerangles 0 0 ang else eulerangles 0 0 -ang
			
			rotate  o rot_box
		)
	)
	
	lookAtFN $Box001 (for o in selection where o != $Box001 collect o)
)

blented · 2012-08-10

I tried to implement this, the following doesn't work even though it seems to match the answer given by Graph.


targetObj = $Sphere001
sel = selection as array
for obj in sel do
(	
	pivotZVector =  obj.dir
	degrees = acos (dot (normalize (targetObj.pos - obj.pos)) pivotZVector)	
	axisVector = normalize (targetObj.pos - obj.pos)
	offsetRot = angleaxis degrees axisVector

	pos = obj.pos
	obj.rotation = offsetRot
	obj.pos = pos
)

Thoughts on what I'm doing wrong?

like this?( local pivPos =

Graph · 2012-08-10

like this?


(
	local yAxis = [0,1,0]
	
	local pivPos = $Teapot007.pos
	local objPos = $Box001.pos

	local ang = acos(dot(normalize (objPos-pivPos)) (normalize (yAxis)))
	
	local rot_box = if pivPos.x > objPos.x then eulerangles 0 0 ang else eulerangles 0 0 -ang
	
	rotate  $Teapot007 rot_box
)

yAxis should of course be the teaPots's local y vector

Attachment

JokerMartini · 2012-08-10

The attached image just clarifies what I'm after.
I just have a selection of objects who's pivots I want to point in the direction of a "targeted object"

It's just a one time deal. The user runs the script and it just changes the pivots rotation accordingly.

It would rotate them in a way that points the Y towards the target object while maintaining the Z axis pointing directly up, perpendicular to the ground.

Attachments

sample.jpg — sample.jpg293 KB

Graph · 2012-08-10

do you need it in realtime?

if not the simplest way is to rotate the object.tm by (anle*axis) and then set the verts to their old coords ;)

assigning?

JokerMartini · 2012-08-10

I'm not sure how you are assigning this to the objects pivot?

objectPoint3 = $Sphere001.pos pivotPoint3 = $.pos PivotZVector = [0,0,1] theAngle = acos(dot(normalize (objectPoint3-pivotPoint3)) (normalize (PivotZVector))) theAxis = normalize(objectPoint3-pivotPoint3)

Graph · 2012-08-09

correct, if the pivot is currently pointing up ;)

pseudoCode:pivot.angleAxisRo

Graph · 2012-08-09

pseudoCode:

pivot.angleAxisRotation axis:normalize(objectPoint3-pivotPoint3) angle:acos(dot (normalize (objectPoint3-pivotPoint3)) (normalize (PivotZVector)))

that should do it ;)

edit: "I'm Batman"

replacing variables

JokerMartini · 2012-08-09

Would this be used in place of the PivotZVector Batman? PivotZVector = [0,0,1]
objectPoint3 = (object to which pivot will be pointed towards).position
pivotPoint3 = (currently selected object wishing to change).position