Help cutting a hole in a curved solid

I am trying to cut holes in the bottom portion of a wood lamp. All shapes were drawn in SU and I think I am doing everything correctly by extruding the shape I want to cut out through the solid and then deleting the intersection, but the holes do not come out perfectly clean. There are weird artifacts and small sections that are not closed that will be an issue for the CNC router. I have attached the file so you see what I mean. thanks
Danmushroom desk lamp29.skp (4.5 MB)

You are encountering SketchUp’s small edge tolerance: very small edges can exist in a model, but SketchUp will “clean them up” when you first create them if they are very short. It has to do this because computers use imprecise arithmetic and points that ought to have matched may be slightly displaced as a result. The workaround is to work at an enlarged size while doing the intersection and then scale down to the real size afterward. One very good way to manage this is “the Dave method” - search the forum and you will find lots of advice about using it.

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Are you using SketchUp Shop or SketchUp for Schools? Your profile seems confused. Or are you using SketchUp Pro as indicated by the category you selected for this thread?

As Steve suggested, the Dave Method will help you get around the tiny face issue.

I’m guessing this is the kind of thing you’re after. The exact approach depends on which version of SketchUp you are using.

I am using Sketchup Pro, sorry for the confusion. I just enlarged it to 3ft tall and that helped somewhat, but it is still a bear to delete all the little intersecting pieces inside the stem. Is there a way to do that faster? DaveR, your model looks perfect! That would take me forever.

Please correct your forum profile.

I remade the shade to give it some thickness and make it solid as a component. Then I made the cutter shapes 3D and made them a solid component. After that Subtract cut the holes in a couple of seconds.

I corrected my profile. I am looking at the shade stem now and it has 3/4" thickness. Is that not enough? It is a component but I need to explode it to intersect the shapes. I feel like I am missing something… I can’t mess w/the interior or exterior shape of that stem because the glass that goes in it is already blown to those exact dimensions.

Here’s the basic setup. I don’t know how many opening there are supposed to be so I guessed at three.

There’s a Profile for Follow Me that will give the urn some thickness so that it can be a solid. The urn profile and circle are in a component and the cutters are in a separate component.

Here I’ve copied both components over and scaled up by a factor of 1000. The originals are still in their original location. I’ve run Follow Me on the profile of the urn.

And here you can see they are both identified as solid components.

And here I’m using Difference from BoolTools2 to cut the openings. You could also use Eneroth Solid Tools. The native Solid Tools won’t work for this without some additional gymnastics. After the openings are cut, the large copy can be deleted and Zoom Extents takes you back to the original.


In the model you uploaded, there’s no wall thickness. Yours is on the right in this screen shot. Mine is on the left.

No. You don’t need to explode the component. If you are going to use Intersect Faces, you can just open the component for editing select the faces, right click on the selection and choose Intersect Faces>With Model.

You should not be exploding components or groups simply to edit the geometry inside. Since you are using Laeys/Tags for things and have been exploding components, you’ve got a lot of geometry that is not assigned to Layer 0/Untagged. ALL edges and faces should have Layer 0 or Untagged assigned to them.
Screenshot - 11_25_2020 , 8_34_45 AM

I may not have the internal shape correct but yours has no internal shape. Remember that faces in SketchUp have no thickness.

I gave the shape some thickness so I could get a solid component to be able to use the Difference or Subtract tool to cut the openings.

Ok, thanks for all that. I think I need to download the plugins you mentioned and redo the urn. I had made it by creating the outside shape as a solid and then the inside shape as a solid and subtracting the inside from the outside. I will redo it as a single shape this time. BTW, there are supposed to be 6 cutouts total, 3 sent all the way through both sides to make 6. I also don’t understand why your shapes are all smooth and pretty and mine have horizontal lines. I am guessing that is because you drew them differently in SU. Hope that doesn’t matter though. I have a little work in front of me. thanks again

It is no doubt based on workflow, but in the end is purely a matter of applying soften and smooth to the shapes. In SketchUp everything is made up of straight edges and flat polygonal faces. But softening and smoothing tell SketchUp to manipulate the shading on the view so that things look smooth.

As Steve wrote, it’s basically down to softening edges. The main difference in workflow was to weld edges so the extruded shapes were smoothed from the beginning but using Soften/Smooth works, too.

Holy ■■■■, BoolTools is amazing! Best $20 I ever spent. That urn looks so good now, it came out perfect.