Tips & Tricks - Digital Architecture

EXTRACTING CONTOUR LINES FROM MESH

[site axon] This page outlines a method for extracting contour lines from a mesh. This can be helpful for extracting accurate 2D information from a complex mesh. The illustration to the left shows a mesh for a sloping site for a single family home that drops about 20 feet from front to rear.

1. Set your 3D Window Settings to Internal Engine, Hidden Line

[3D Window Settings dialog box]

2. Set your Parallel Projection Settings to Top View, Azimuth = 270˚

[Parallel Projection Settings dialog box]

3. With the mesh selected, right-click and select Show Selection/Marquee in 3D (so only the mesh appears in the 3D Window).

[3D Window]

4. Set your 3D Cutting Planes: In the “Z” box, enter the height of the contour, click the “Z” icon to lock it (or hit “Z:” on the keyboard to select this entry box, then option/alt z to lock the value), then draw the Z Cutting Plane in the window above, click above the line to remove all above, set the Fill Material & Edge of Pen Cuts to Custom, and set the pen number for a unique pen (this will help in seeing and selecting the lines).

[3D Cuttings Plane dialog box]

5. Activate 3D Cutaway

[3D Window with cut] 6. Got to the 3D Window, your mesh will be cut at the contour height, the cut line will be the pen previously selected.
* See footnote below for saving the contents of the 3D Window with the mesh and cutting plane for repeating this procedure more easily if the mesh is later altered.

7. Select the Marquee Tool, flat marquee option, select the area around the contour line and copy.

8. The Copy dialog box that appears, select Scaled Drawing, Edges, and Remove Redundant Lines

[Copy... dialog box]

9. Go the 2D Window and Paste, the contour lines will come in over the mesh matching their position from the 3D Window

[2D Window with lines]

10. Repeat steps 4 to 9 for each contour level

11. Now you can select the lines, change their layer, line type and other attributes depending on your drafting standards. You can add text for the contour heights. If you have a mesh showing the existing grade and a new mesh showing proposed grades, then lines from both meshes can be extracted to show grading changes.

[Copy... dialog box]

*The 3D Window with the Mesh and Cutting Plane can be preserved with a 3D View: after generating the 3D Window, use the Organizer to pull the Generic Axonometry from the 3D List into the View Map, give the view a descriptive name (for example: Contour -10’), click the Settings button and click the Get Current Window’s Settings to save the settings of the 3D Window, including the Cutting Plane. This allows the contours to be regenerated more quickly if the mesh is later altered.

EXTRACTING CONTOUR LINES FROM MESH
		This page outlines a method for extracting contour lines from a mesh. This can be helpful for extracting accurate 2D information from a complex mesh. The illustration to the left shows a mesh for a sloping site for a single family home that drops about 20 feet from front to rear.


5. Activate 3D Cutaway
		6. Got to the 3D Window, your mesh will be cut at the contour height, the cut line will be the pen previously selected. * See footnote below for saving the contents of the 3D Window with the mesh and cutting plane for repeating this procedure more easily if the mesh is later altered.