How do I create curved surfaces from arcs I've drawn?

Finial.skp (596.5 KB)

I am attempting to add curved walls to the attached drawing so that I essentially have a pyramid-like shape with walls that follow the arcs I have drawn, but I can’t seem to figure out how to do it. I’ve tried several google inquiries, but most seem to want me to install several extensions that apparently don’t work with my version. Can anyone help? Thanks for your time!

You can eiyher do it manually by connecting the end points of two adjacent arcs with horizintal ines…then copy the whole face around the square.
Or you can use Fredo6’s Curviloft plugin from the Sketchucation.

You’ll also need the Librfredo library file.

You could explode each arc and turn on ‘Endpoints’ = (say) 6 to see which endpoints to connect with horizontal edges with the ‘Line’ tool, just as @AlanF said.

Since all four curved surfaces look/are the same, create one and rotate copy it 3 times.

But as it is now, at least one of your pair of arcs does not seem to have coplanar edges per segment. You can’t create the surface with only horizontal edges for this surface. See red edges in image:

Hi grey machine, hi folks.

Click in sequence on the scenes tabs of this SU file for ideas.


Finial.skp (613.6 KB)

Just add one line and use follow me.


Thanks everyone, especially Box for a rather easy fix! Now I just need to work on hollowing out the interior as this shape needs to be a shell with a thickness of about 1/4" rather than a solid object.

Use the Joint Push/Pull plugin with the option to retain original faces.

Or as an alternative to Alan’s suggestion, draw the profile with the proper thickness in the first place and use Follow Me on that.


Finial.skp (599.7 KB)

Those look great! Here is what I did (I forgot that it needed to be shorter and have a pyramidal cap). I went about mine the hard way, offsetting a square in the middle from the bottom view, deleting it, then creating surfaces in the interior to give the desired wall thickness (3/8" in this case). Does anyone see any errors? As far as I can tell, this is at the final dimensions.

Yes. You need to correct the face orientation. The blue faces should be on the inside. There are internal faces that should be removed and you have a place of zero thickness just above the bottom.

Additionally, is there an extension that calculates volume? Eventually I am going to cast this in bronze and the thin walls are intended to cut down on the weight problem; the original (the taller, solid model that I originally started modeling) came out to be an unacceptable 30+ pounds. This one should be within the limits of my foundry, but it would be nice to know the exact weight I will be dealing with; if I need to make the walls thinner, or if I can make them thicker while keeping a reasonable weight, it would be best to do that here.

I’m not sure how to do those things, but I’ll play around with it and give it a try; Thanks!

I would suggest that you redraw the whole thing and not use such a complex approach to it. Draw the profile similar to the way I showed in my screenshot. Make the cross section profile a single face. Then use Follow Me to extrude it. If you’re going to cast this thing you can’t have that zero thickness area near the bottom or you’ll wind up with two pieces.

I understand what you are saying now; Thanks, I’ll give it a try!

If you make a solid (must be a Group or Component), SketchUp’s entity info will show the volume when you select the solid. No extension needed!

I re-drew the model using DaveR’s simpler method, a profile slice that I extruded using Follow Me around a perpendicular plane at the base.

Finial.skp (118.6 KB)

I smoothed out some of the hard edges in the interior by thickening it so that there will be less of a chance of failure when I cast it. I also grouped it and got a volume of 29.5034 in³, which means it will only weigh 9.32 lbs, a much better weight than what I was previously getting!

Much better. You just need to correct the face orientation now.

I’m not sure what you specifically mean; I think you mean that Sketchup utilizes specific color shades to indicate an interior surface versus an exterior one, but it appears correct to me although obviously I am missing something. How do I go about correcting it? That may make the error more readily apparent to me.

Yes, SketchUp indicates front and back sides of faces with different colors. The default back face color is blue and the front is white. You have most of the faces on your model inside out. You can select the faces, right click on one and choose Reverse Faces.

Smoothing edges in SketchUp only makes it LOOK smoother.
The ‘faceting’ resulting from the segment count in a curve will not change in the 3d-printed version.
The make it actually smoother when printed you need to change the number of segments in the arcs used in the profile face you are using to FollowMe.
It’s best to set an arc’s segment count as you create it.
But if an arc in not already incorporated into a 3d form, then you can adjust it in 2d by selecting that arc and using Entity Info to change its segmentation.