WorldViz User Forum - Clipping Plane

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- - Clipping Plane (https://forum.worldviz.com/showthread.php?t=2494)

envisC

02-03-2010 11:21 AM

Clipping Plane

Is there a way to create a clipping plane that I can manipulate? We want to be able to interactively create cross sections of our models.

Jeff	02-03-2010 12:10 PM

You can use window.clip or window.frustum to set the clipping plane.

envisC

02-03-2010 01:00 PM

We explored these options, but they don't provide the functionality that we need. What we really want is something similar to glClipPlane or osg::ClipNode, not just near and far clip planes for the camera.

farshizzo

02-03-2010 01:47 PM

Here is a sample script that shows how to apply a custom clip plane on a model (Note: the clip plane values are specified in global coordinates):

Code:

import viz

import vizact

import vizmat

viz.go()



model = viz.add('gallery.ive',pos=(0,0,10))



model.clipPlane([1,0,0,-3])



slider = viz.addSlider(pos=(0.5,0.1,0))



def SetClip(p):

        model.clipPlane([1,0,0,vizmat.Interpolate(-3,3,p)])

vizact.onslider(slider,SetClip)

envisC

02-09-2010 01:31 PM

This is great! Thank you! Did I just miss this in the documentation?

pitbool

10-22-2012 04:53 PM

Hi,

I have a list of around 5000 nodes on which I want to apply the clip operation.

I created a scenegraph with a parent node to all of these nodes. Then I created a clipplane to the parent node.
The clip plane works fine on the parent node. However the clipplane doesn't seem to apply to any of the children. I have tried with all the three op options (viz.OP_TRAVERSE, viz.OP_OVERRIDE, viz.OP_ROOT) in the clipplane definition (http://docs.worldviz.com/vizard/comm.../clipPlane.htm) but none worked.

Could farshizzo or anyone else please give any pointers to my problem?

Thanks in advance!

pitbool

10-22-2012 05:13 PM

Please let me add that when I said "I created a scenegraph with a parent node to all of these nodes", I meant I used the command .setParent to set the parent of all the ~5000 nodes to one single node object.

Thanks.

pitbool

10-23-2012 01:26 PM

I have found a way to do this - by applying the clipPlane to every node of those ~5000 nodes. I was initially hesitant to try this out, due to the limited number of planes openGL has. But I found that multiple instances of node3d.clipPlane may map to the same clipping plane of openGL. So that solved my problem.

farshizzo

10-23-2012 01:36 PM

It's difficult to say what you are doing wrong without seeing any code. The following sample applies a clip plane to a root node and affects all children. It works for me in Vizard 3 and 4:

Code:

import viz

viz.go()



root = viz.addGroup()



for x in range(20):

        viz.add('logo.ive',pos=(0,0,x),parent=root)



root.clipPlane([1,0,0,0])



import vizcam

vizcam.PivotNavigate(distance=10)

Also, in the future please post questions in new threads.

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