Resolving this surface?


I am trying to resolve one surface on this model. The top surface is currently flat, but I would like it to be domed. There are two curves that cross each other at the top of the model that capture the form I am trying to make. Once the domed surface is in place I was planning on transitioning the dome into the side surfaces with a G3 fillet. I am attempting to model this form without really heavy isocurve surfaces, as I have been told this is bad modeling practice. Any suggestions on how to approach this surfacing puzzle? 3dm file attached.

Thank You,


Form.3dm (1.4 MB)

One other note: I’d like the domed surface where the curves cross to have G3 surface continuity. All the approaches I have tried so far have left visible surface breaks where the crossing curves of the dome are.

How do you propose to blend out the corner creases, or do they continue to the top?

I was planning to build surface fillets on all hard corners once the initial form had been blocked in.

Fillets are circular so degree 2. You aren’t going to get G2 or G3 blends with fillets.

I build fillets with g3 curves, not using the fillet tool.

Hi Justin,

The two curves do not quite intersect: adjust one or both.

I would round off the 1/4 position edge before creating the dome.

Leaving a kink makes the dome harder to create and will require it to be creased at least a little.

  1. Move everything so the centre of the dome is at the origin. Then work on one quadrant and only when correct mirror it twice to create the whole.
  2. Rebuild your curves to be as simple as possible and match the point count and degree for curves on opposite sides of each panel.
  3. Create new panels from the curves using _EdgeSrf.
  4. Extrude the dome curves away from the quadrant to provide helper surfaces to match the dome edges to.
  5. Be prepared to move control points to bring recalcitrant short edges together after matching the long edges (axes) of the dome.
  6. If you leave the 1/4 position crease in situ then the dome quadrant will be a polysurface. Be prepared to explode it and line up control points to minimise the creasing in the dome emanating from that point.
  7. Check for naked edges repeatedly. Check the curvature graphs repeatedly.

This is pretty close, but without curving the 1/4 edge, so with four slight creases in the dome:

Also, you might feel that in simplifying the curves I have in some places allowed too great a deviation from your originals, in which case you will want heavier surfaces.

Form 001.3dm (1.2 MB)


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All your feedback has been really helpful. I’m going to proceed modeling on this project and expect far fewer hang-ups. Thank You!