I was going to mention the same as Ralph, and also seems like there may be the same calc in the Frustum Culling, but I don't want to steer anyone down the wrong road :O
On Fri, Jun 26, 2009 at 3:10 PM, Ralph Brooker <[email protected]> wrote: > Would it be possible (in theory) to use algorithms in Away3D’s > INTERSECTING_OBJECTS renderer to build a list of line segments that > represent the intersections of the triangles that make up the two > intersecting objects? > > > > *From:* [email protected] [mailto:[email protected]] *On > Behalf Of *Li > *Sent:* Friday, June 26, 2009 3:06 PM > *To:* [email protected] > *Subject:* [away3d] Re: Mesh intersection on to a 3D Plane > > > > If you study the mathematical problem of intersection between 2 planes, you > could actually find all the parametric equations of the intersection lines > between your plane and each face, and possibly project them into a flat > graphic if needed. > > You would have to sweep all the faces and compare them to your plane. Even > though, faces are not infinite in extent as planes are... so here you would > have a bit of a problem... quite a problem in fact! So that would be left to > your research and creativity. > > Anyway, just thoughts that come out as I read. Hope it helps... > > On Fri, Jun 26, 2009 at 6:21 PM, joar <[email protected]> wrote: > > > Thanks Li, > I also thought about the method you suggested, but before going that > path I wanted to know if there are any other option. > > Fabrice, I have an object mesh and I want to cut it with an arbitrary > plane (typically an xy-plane at different z-position determined by an > slider). I want to build (and display) the 2D polygon of that cut. > See the following skematic: > http://www.softeng.cse.clrc.ac.uk/everest/docs/post-processor/post_html/img10.gif > > joar > > > On Jun 26, 12:11 am, Fabrice3D <[email protected]> wrote: > > what is it you want to do exactly? > > > > is it the mountain that must be separated from sea level? > > the mesh cut in half? > > ? > > > > Fabrice > > > > On Jun 25, 2009, at 11:55 PM, Li wrote: > > > > > Sounds like a difficult task to me... > > > > > All I can think of is using a camera, placing it at a strategic > > > point and setting up materials on the geometries so that if you > > > render it and process it you could get an image of what your > > > polygons might look like. All this with a precise renderer. > > > > > Thats just a cheat though, if you want precision, I'm afraid this > > > would involve some complex mathematics. Plus, I'm not sure if any > > > part of the engine handles anything like this. > > > > > Hope it helps! > > > > > > On Thu, Jun 25, 2009 at 6:18 PM, joar <[email protected]> wrote: > > > > > Is there any way to compute the intersection between a Mesh object and > > > a 3D plane? > > > I have some meshes that I want to intersect with 3D planes at > > > arbitrary positions and draw the resulting 2D polygon on that plane. > > > thanks, > > > joar > > > -- ___________________ Actionscript 3.0 Flash 3D Graphics Engine HTTP://AWAY3D.COM
