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It's time to load the problemtype. Go to Data->Problemtype->Examples->cmas2d_customlib. The first you can see is a window like this:
This window helps you to generate a random 4 sided surface. For this example let's click Random surface and get an auto-generated surface. You can click continue and create your own surface. This is the surface I'll work with:
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Your tree should look like this:
Writing the calculation files
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