Projecting Points onto .stl Defined Surface

mchurchf · August 17, 2012, 17:50

I want to read in a .stl file and use it to define a surface. Then given an x,y location, I'd like to project onto the surface to find the z height. Can anyone help with how to do that. The surfaceDisplacement boundary condition that can be used for the "pointMotion" field with the moveDynamicMesh solver seems to be able to do this, but I can't figure out how to do that. I've taken the "transformPoints" utility and modified it to take a block mesh made with "blockMesh" and translate points vertically to conform to an analytical surface definition at the bottom, but now I want to have the ability to conform to a general surface definition that comes in the form of an .stl file.

Thank you,

Matt

l_r_mcglashan · August 17, 2012, 18:04

Would functions such as findLine in triSurfaceMesh be what you're looking after?

mchurchf · August 17, 2012, 18:13

Laurence,

If I'm reading the code correctly, one would give start and end point fields of a segments, and findLine will return the intersections? If so, that's pretty neat.

Matt

l_r_mcglashan · August 17, 2012, 18:19

Yes and an octree is used for the search, useful if you have a large surface. Hope that helps!

August 17, 2012, 17:50	Projecting Points onto .stl Defined Surface	#1
mchurchf Member Matthew J. Churchfield Join Date: Nov 2009 Location: Boulder, Colorado, USA Posts: 49 Rep Power: 19	I want to read in a .stl file and use it to define a surface. Then given an x,y location, I'd like to project onto the surface to find the z height. Can anyone help with how to do that. The surfaceDisplacement boundary condition that can be used for the "pointMotion" field with the moveDynamicMesh solver seems to be able to do this, but I can't figure out how to do that. I've taken the "transformPoints" utility and modified it to take a block mesh made with "blockMesh" and translate points vertically to conform to an analytical surface definition at the bottom, but now I want to have the ability to conform to a general surface definition that comes in the form of an .stl file. Thank you, Matt

August 17, 2012, 18:04		#2
l_r_mcglashan Senior Member Laurence R. McGlashan Join Date: Mar 2009 Posts: 370 Rep Power: 23	Would functions such as findLine in triSurfaceMesh be what you're looking after? __________________ Laurence R. McGlashan :: Website

August 17, 2012, 18:19		#4
l_r_mcglashan Senior Member Laurence R. McGlashan Join Date: Mar 2009 Posts: 370 Rep Power: 23	Yes and an octree is used for the search, useful if you have a large surface. Hope that helps! __________________ Laurence R. McGlashan :: Website

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August 17, 2012, 18:13		#3
mchurchf Member Matthew J. Churchfield Join Date: Nov 2009 Location: Boulder, Colorado, USA Posts: 49 Rep Power: 19	Laurence, If I'm reading the code correctly, one would give start and end point fields of a segments, and findLine will return the intersections? If so, that's pretty neat. Matt