<div id="RTEContent"><br> Hello users, please forgive the newbie/linear algebra ignorant question...<br> <br> I am attempting to position a vtkPlaneSource such that it has a specific height and width (is rectangular) at a specific global coordinate with a specific normal... I have been having trouble using the vtkPlaneSource interface to get the desired orientation... if i do something like<br> ->SetOrientation(0,0.0)<br> ->SetPoint1(width,0,0)<br> ->SetPoint2(0,height,0)<br> and then <br> ->SetCenter( with the location I want the center to be at in global coords)<br> ->SetNormal (with the actual normal i want the plane to have)<br> I dont get what I expect, im sure this is not a surprise to people who know whats going on, I read the documentation and it says something about how the normal specifies a rotation or something...well how do I use that so that the final orientation has the normal I want??? or am i totally missing something?<br> <br> Any pointers here would
be really appreciated, obviously im not too comfortable with transformations etc...<br> in fact, i have another problem, i am also attempting to orient a vtkCylinderSource along a specific vector (including the length), i have projected the vector into two planes, maybe xz to get an angle around the y axis and then the yx axis to get a rotation around the z axis etc... then i attempt to use a vtkTransform and a vtkTransformPolyDataFilter to orient the cylinder but again, i dont get what i expect. I always see/hear about rotation matrices, but are those rotations relative to the original orientation? or would say a rotation around y axis after a rotation around the x axis would actually rotate about the rotated y axis? Are the rotations cummulative? I guess what I am saying is people always show rotation matrices but what i dont get is given a desired orientation, how do i figure out the rotations that get me there, i know there are multiple ways each time...<br> <br>
anways, any help at all would be greatly appreciated, again<br> thanks for your time<br> -tim<br> </div><p>
<hr size=1>Yahoo! Shopping<br>
Find Great Deals on Gifts at <a href="http://shopping.yahoo.com/;_ylc=X3oDMTE2bzVzaHJtBF9TAzk1OTQ5NjM2BHNlYwNtYWlsdGFnBHNsawNob2xpZGF5LTA1
">Yahoo! Shopping</a>