[vtkusers] vtkCollisionDetection Coloring Colliding Cells

Goodwin Lawlor goodwin.lawlor at ucd.ie
Mon Nov 10 12:53:05 EST 2008


Hi Prabhat,

prabhat246 wrote:
> Hey all,
> I am able to use vtkCollisionDetection class get the colliding cells. 
> But how if I want to color the colliding cells into differnt color?? 

The simplest way to do your own colouring of cells may be to use 
vtkProgrammableAttributeDataFilter to loop through the ContactCells list 
and create whatever scalars you want. A 4 component vtkUnsignedCharArray 
can be used to represent RGBA for each cell you want to colour. 
Alternatively use a single component array and map the values through a 
LUT to get the colours you want.

> and How can I stop the the collission means One object should not get into
> other. If I stop the interaction it will stick to other forever. isn't it??

One way on getting your actors to behave like solid objects is to change 
the actor origin to the first point of contact. Actors tend to roll off 
each other (there's no mechanics involved!).


vtkRenderer ren
    ren AddObserver EndEvent ChangeOrigin

proc ChangeOrigin {} {
     if {[collide GetNumberOfContacts] != 0} {
         set pts [[collide GetContactsOutput] GetPoints]
         set xyz [$pts GetPoint 0]
         eval actor1 SetOrigin $xyz
         eval actor2 SetOrigin $xyz
     } else {
         actor1 SetOrigin 0 0 0
         actor2 SetOrigin 0 0 0



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