Trouble creating a 3D Sandbox model with a DWG contour map


I am attempting to import a contour map from AutoCAD into SketchUp to create a 3D Sandbox model. I can import the DWG file but I am unable to seperate the contour lines in order to adjust each individual contour. I tried exploding the lines but I get a million little bits of lines and the lines. Any help would be greatly appreciated.


Really hard to say from your description what the problem is or even whether there is an actual problem. I’m really not sure what you mean by, “I tried exploding the lines.” You mean you exploded the group containing the lines? You mean you used the “explode curve” command?

Please upload the model so we can see what’s going on.



Thanks Gully.

I’ll attempt to clarify…I am bringing a DWG contour linework basemap into SketchUp, but when I do that it imports as one object. In order to manipulate the contours to different heights, the tutorial recommends exploding the object into its components. When I explode the imported object, each contour line becomes an aggregate of thousands of little objects.

If there is any way to keep the lines intact when exploding so that I can manipulate each line that would be extremely helpful.

I tried to attach the SketchUp File but it is too large of a file size. I tried grouping one line, but it seems like a daunting task to select all the parts of each line and group them in order to create a complete contour line.

Apologies if that is unclear. Thanks in advance for your help!


It would help us help you if you uploaded the SketchUp model in the state immediately after the DWG import.
Perhaps open a new file > Import the DWG into SU > Save the file > Upload to the 3D Warehouse

You can upload the model to the 3D Warehouse from within SU via File > 3D Warehouse > Share Model
Post the 3DWH link and or the exact name back here so we can find it and have a look.


Thanks Geo. I uploaded the model to 3D Warehouse with the below name. I could not find the link to share, but hopefully you can access the model with the name.

Name: ThreeHolerModel.skp

I appreciate the help!


Yeah, you have to go back to the 3DWH to get the link.

The first thing to do is go to the Layers manager and delete all the extra layers.
You need to move everything back to the Default Layer 0.
Then study this: Does SketchUp Support Layers — SketchUp Help

Here we are…


Since, by definition, each contour is separate and distinct from adjacent contours, you should be able to select an individual contour line simply by triple-clicking (select all contiguous objects). This doesn’t work with your model because there is an outline running around the contour map which effectively connects all the contours touching the rectangular outline.

I have carefully removed the rectangular outline, leaving only the contours, which are now easily selectable individually by triple-clicking.

Here’s a blowup through the thickest part:



It often helps to run this tool prior to creating the TIN with the From Contours tool.
Simplify Contours Tool by Trimble SketchUp Team — Extension Warehouse

In this instance it reduced the 43,084 edge count to 43,009, a mere 75 edge reduction.

After you clear away the interconnecting edges as Gully recommends, you might also consider welding the segments of each contour into a curve aka polyline.
Weld by Smustard Team — Extension Warehouse