Mate/blend surface

Hey folks, I need help here.

  • I’m making a part that mates to an imported scanned mesh.
  • the surface opposite the mating surface to the scan is planar.
  • each surface has a different shape.

Attached photo:

  • green is scanned mesh.
  • gray part is mated part from projection.
  • light blue us the planar face.

What I can’t figure out:

What I’ve done:

  • projected the shape of the mating surface. Extruded the new shape. This gave me a mated surface that is offset with uniform thickness.

What I thought I could do but doesn’t work;

  • Project profile shape which would create a face geometry. Duplicate this face and move it outward to a given thickness offset. Then create the smaller planar face shape. This would give me three faces (2 complex curve, 1 planar) that I can loft.

Thanks for your help!

Hi @Alano
Something like this maybe?

Draw the two sketches you want to loft.

Loft them.

Then use “replace face” on the face of the loft with the curved surface.


Hi Nathan, thanks for the reply. I have tried replacing face. I wish there was a warp or bend function. Please take a look at this image. See how the side part wraps around the helmet? There is a thickness to the side walls that are normal to the surface of the helmet. Then the inner channel (with vertical holes) is planar. So I’m looking at a shape that is uniform shape as it wraps and then have a flat planar area inset.

So what is did is to:
-create a shape that matches the helmet scan ( since you can’t snap to a scan). This new shape closely matches the curvature of the helmet. This is a temporary geometry just so I can project a shape to it.
-i then projected the new profile onto that newly created helmet shape.

  • I then extruded that projected face to create a part that is now “wrapped” around helmet. So if you look at this photo you see the helmet with that side part wrapped to the helmet.
  • NOW, the issue is my new wrapped part is stuck to the temporary helmet surface I made of the scan. I cannot separate my new “wrapped” part.

-likewise, before I extruded the projected face I tried to select that projected face and duplicate it with the hope of using it in a loft function with other faces, however, I can’t duplicate that face.

Thanks for your help!:grinning_face_with_smiling_eyes:


Oh Duh! All this time I’ve been trying to separate the projected face from that temp surface behind it. Just now I simply lofted the planar surface to the top face of the wrapped part and it worked! Duh!
So this is the shape I want BUT it still can’t separate this gray part from the green surface. I tried selecting faces of the green shape to delete but no luck. How can I separate the gray part?


@Alano I ran into this same problem. When projecting a sketch on the rounded surface, all you can do is offset the face from the round body, which defaults to a union of the body. There is no option to extrude from the projected edges, and set as a new body.

I can’t figure out why this is.

But in the meantime, maybe make a copy of the scanned surface without the lofted/projected body, then subtract it from the scan that has the lofted/projected body attached, then you would be left with just the grey part (and original scan if you select “keep removed bodies” while subtracting.)

Wow, awesome project!

Because 3d splines are currently not supported, curves projected to a rounded surface became edges on the surface. For extrusion, planar curves are expected, this is why you can only apply the offset surface on the enclosed area.

For the wrapped shape, can you please try to

  1. Make a copy of the scanned helmet
  2. Scale it up
  3. Draw a body around it and subtract the scan from the body. It will result in the scaled up negative of the helmet, so you will have a distance between the original helmet and the subtracted body.

Then you can model any shape on the side of the helmet, the main thing is to make it bigger to get a clear intersection with the original scan and the scaled body.
When you are ready with the desired cross section, subtract the helmet from it, then subtract the scaled body from it to get the wrapped shape you are looking for.
Please let me know if a video would help you


Hey KPeter, thanks for the reply. You made me rethink what I was doing!

  • i copied the helmet surface and moved it outward by a given distance.
  • I then extruded the outer base profile into the copied helmet surface and did a intersect Boolean.
  • I then copied the original helmet scanned surface again and this time subtract Boolean with the newly created intersected shape. This gives me a base shape that contours the helmet surface.
  • I then brought in my flat planar face and lofted it with the top surface of the base shape.

Thanks for your help!