Offset surface problem

Hi everyone,
I have only been using rhino for about 3-4 weeks and am having some problems thickening my models for 3D printing. To make these models i have been using the network surface command to first create the shape i want. I then split that body in half and do surface detailing on one half and then mirror the halved surface so it will be symmetrical and return to one full body/surface. I then continue to to add surface details once the two halves are joined. To make the surface details i use the split and extrude curve command to create the shapes on the original network surface body/half. And using sweeps and lofts to join these split/ removed areas to create the surface detailing. Once i am happy i then use the join command to join all the surfaces to make one poly surface, and then use the offset surface command to try and thicken the model at a thickness of 2mm.

However when i try to thicken my model/surface it glitches and has problems and say failed to create solid, i notice it has problems particularity where straight lines are used for the sweeps/ lofts on the surface. I am not sure if this is because my sweeps/ lofts are at too harsh of an angle or if i am using the wrong techniques to model these surfaces. i have also played around with the tolerances of the offset surface but i has little affect.

sorry if this is too long, Any help would be much appreciated, thank you.

Hi Matt,

That’s a cool piece of modelling for a beginner, well done!

You are likely to get more focussed advice if you upload your model with your post. But in terms of general principles here are a couple of suggestions.

  1. Use the Show Edges analysis tool to highlight naked edges between parts of your outer surface model to indicate where joins may have failed.

  2. With a complicated shape like this, offset surface may struggle to deal with things like self intersections of the new surface. If you are using offset surface with the make solid option, try without, and look at offsetting surfaces individually and then extending, trimming, filleting and patching to create the inner surface. You will find it helpful to put inner and outer surfaces on different drawing layers so you can turn off the outer surfaces while working on the inner. Once you have an inner surface, create the faces between inner and outer using, for example, sweep 2 rails, to join them into a solid.


Thanks for the advice I will give that a go!