[GAMBIT] Plotting/Meshing a Contour Map (3D hill)

VU_Engineer · December 7, 2009, 16:55

I'm trying to model a 3D hill and have been provided with a contour map.

I'm trying to find a more accurate way to plot the points on the map than choosing random points and adding them point by point into GAMBIT by hand

someone suggested 3DField which imports contour map images, creates points along each contour line, and then creates lines between those points. I've been having trouble though and am close to giving up on this software package, because its also trying to to creates points of the contour elevation numbers. it makes sense that it's trying to do this, because how would it know that it's a number and not a countour line, but what contour map would not have elevations on it?!

anyways, some sort of a direction would be very helpful

PSYMN · December 8, 2009, 13:13

You can pick a curve, such as the zero line... And create points along it, create a curve thru the points and then set it to the zero Z value. Then do the same for the 10 ft line, except move it up to the Z=10 plane, etc. The curves you create will represent the contours. Do this for all the curves and then build a loft surface between them. Delete the original layer that had the numbers on it.

If your model came in with selectable curves, you can skip the first steps and just translate/move them up to the correct elevation in your drawing and proceed from there.

If you have access to something like Autodesk Revit (or perhaps other architectural CAD tools) they have a nice semi-automated way for you to do this from a scanned topography image.

VU_Engineer · December 8, 2009, 21:28

Quote:

Originally Posted by PSYMN

You can pick a curve, such as the zero line... And create points along it, create a curve thru the points and then set it to the zero Z value. Then do the same for the 10 ft line, except move it up to the Z=10 plane, etc. The curves you create will represent the contours. Do this for all the curves and then build a loft surface between them. Delete the original layer that had the numbers on it.

If your model came in with selectable curves, you can skip the first steps and just translate/move them up to the correct elevation in your drawing and proceed from there.

you're saying to do this within 3DField? or are you talking about Gambit

after you create a curve through points, how do you translate the curve up?

VU_Engineer · December 8, 2009, 21:40

OK, so I've figured away to export all the points from 3DField to a text file

then I can open this up on excel, add an additional column for elevations, and then export to a Tab Demented txt file that I can load vertex points from in Gambit

this means I'd have to go in and draw every line between each point by hand, and I'm dealing with 60,000+ points....

wouldn't I think also have to connect the points on each contour line with points? and then go through and make all the faces by hand?

there has to be an easier way to do this

VU_Engineer · December 8, 2009, 22:50

UPDATE:

I was able to import the the contour lines as connected edges

I'm now translating edge contour line of connected edges to the desired heights, and then making a face of height

i'm back to the problem that I can't connect the faces to each other... any suggestions?

PSYMN · December 10, 2009, 18:24

If you have a field of points (XY) with elevations (Z), that is a point cloud (XYZ). There are many freeware programs that will create an STL surface from a point cloud.

http://www.google.com/search?q=point+cloud+to+STL

I am more of an ICEM CFD expert, and I know that ICEM CFD could create the faceted surface from an imported point cloud. Perhaps Gambit has a similar tool. If not, try one of the above and bring the STL surface into Gambit.

AvaShahrokhi · January 28, 2014, 07:59

Hi everybody

I am trying to do the same. In my case I generated the hill shape in Solidwork and import the stl file to ICEM. It is easier I guess. But I need to merge it with the ground boundaries. I have tried a couple of things but when I do the meshing, the hill shape is not recognized and the mesh lines pass through the hill.

Does anybody have any suggestion so that I can model the hill shape correctly?
I am using blocks and generate structured mesh.

thank you!
Ava.

December 7, 2009, 16:55	Plotting/Meshing a Contour Map (3D hill)	#1
VU_Engineer New Member James Join Date: Dec 2009 Location: Nashville, TN Posts: 21 Rep Power: 16	I'm trying to model a 3D hill and have been provided with a contour map. I'm trying to find a more accurate way to plot the points on the map than choosing random points and adding them point by point into GAMBIT by hand someone suggested 3DField which imports contour map images, creates points along each contour line, and then creates lines between those points. I've been having trouble though and am close to giving up on this software package, because its also trying to to creates points of the contour elevation numbers. it makes sense that it's trying to do this, because how would it know that it's a number and not a countour line, but what contour map would not have elevations on it?! anyways, some sort of a direction would be very helpful

December 8, 2009, 13:13	Follow the isocurves	#2
PSYMN Senior Member Simon Pereira Join Date: Mar 2009 Location: Ann Arbor, MI Posts: 2,663 Blog Entries: 1 Rep Power: 47	You can pick a curve, such as the zero line... And create points along it, create a curve thru the points and then set it to the zero Z value. Then do the same for the 10 ft line, except move it up to the Z=10 plane, etc. The curves you create will represent the contours. Do this for all the curves and then build a loft surface between them. Delete the original layer that had the numbers on it. If your model came in with selectable curves, you can skip the first steps and just translate/move them up to the correct elevation in your drawing and proceed from there. If you have access to something like Autodesk Revit (or perhaps other architectural CAD tools) they have a nice semi-automated way for you to do this from a scanned topography image.

December 8, 2009, 21:40	Gambit	#4
VU_Engineer New Member James Join Date: Dec 2009 Location: Nashville, TN Posts: 21 Rep Power: 16	OK, so I've figured away to export all the points from 3DField to a text file then I can open this up on excel, add an additional column for elevations, and then export to a Tab Demented txt file that I can load vertex points from in Gambit this means I'd have to go in and draw every line between each point by hand, and I'm dealing with 60,000+ points.... wouldn't I think also have to connect the points on each contour line with points? and then go through and make all the faces by hand? there has to be an easier way to do this

December 10, 2009, 18:24	Point Cloud	#6
PSYMN Senior Member Simon Pereira Join Date: Mar 2009 Location: Ann Arbor, MI Posts: 2,663 Blog Entries: 1 Rep Power: 47	If you have a field of points (XY) with elevations (Z), that is a point cloud (XYZ). There are many freeware programs that will create an STL surface from a point cloud. http://www.google.com/search?q=point+cloud+to+STL I am more of an ICEM CFD expert, and I know that ICEM CFD could create the faceted surface from an imported point cloud. Perhaps Gambit has a similar tool. If not, try one of the above and bring the STL surface into Gambit.

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December 8, 2009, 22:50		#5
VU_Engineer New Member James Join Date: Dec 2009 Location: Nashville, TN Posts: 21 Rep Power: 16	UPDATE: I was able to import the the contour lines as connected edges I'm now translating edge contour line of connected edges to the desired heights, and then making a face of height i'm back to the problem that I can't connect the faces to each other... any suggestions?

January 28, 2014, 07:59		#7
AvaShahrokhi New Member Ava Join Date: Nov 2013 Location: UK Posts: 17 Rep Power: 13	Hi everybody I am trying to do the same. In my case I generated the hill shape in Solidwork and import the stl file to ICEM. It is easier I guess. But I need to merge it with the ground boundaries. I have tried a couple of things but when I do the meshing, the hill shape is not recognized and the mesh lines pass through the hill. Does anybody have any suggestion so that I can model the hill shape correctly? I am using blocks and generate structured mesh. thank you! Ava.