Getting to a solid Sketchup model

The attached skp shows my drawing of a spool pin (to hold a spool of thread in place on top of a sewing machine). This is not showing as a “solid” under entity info.

The final model will be 25mm across and 42mm high.

This is my first steps into 3D printing and I want to learn how to clean things up in Sketchup before exporting.Singer 503J filleted spool pin-1.skp (179.3 KB)

Hi Terry,

The problem is some internal faces.

Solid Inspector2 would be a useful thing to have. You can get it from the Extension Warehouse. Access it through the Window menu. Also, you can avoid this sort of issue with the right modeling techniques. For a model like this, I would most likely draw a cross section profile centered on a circle and use Follow Me to sweep the profile around.

On a slightly different note, it’s best to be deliberate about drawing circles and drag out the radius on axis. You did that when you drew the circle for the large base disk but not for the smaller circles. In my screen shots the guidelines are parallel to axes. You can see the vertical softened edges don’t meet the guidelines. This can create quite a mess for you.

This shows the model fixed so all the circles are on axis.

Making it from the profile and a circle with Follow Me.

First, thank you for the amazingly fast and detailed response.

I will install Solid Inspector2 and try it out.

In my first attempt at this, I did try to draw a cross section profile centered on a circle and use Follow Me to sweep the profile around. I seem to have a lot of problems keeping my drawing of the profile in plane, and when I did I was still having “open” problems. I was advised that the small diameters I was working with cause problems in Sketchup and that I should try extruding cylinders instead. I will go back and try drawing the cross section profile again and see if my drawing ability has improved any.

I will pay more attention in future to dragging out the radius on an axis. It didn’t occur to me before.

In this drawing, I was able to specify 96 segments for the large (25mm) disk but for the smaller disks I was limited to 48s( or 24s, I can’t remember). Should I be consistent in specifying the number of segments for circles in a drawing or does each circle stand on its own?

An easy way to prevent off plane drawing is to start with a large rectangle. Then make sure you are looking for “On face” inference messages as you go. Erase what isn’t the profile once you’ve closed the loop.

SketchUp won’t create very tiny faces so working with small radius circles and arcs can be problematic. You can end up with holes in the surface which would prevent the model being a solid and 3D printable. An easy fix if you are working in metric units is to set the Units to meters instead of millimeters. Then enter your dimensions as meters. So your 12.5 mm radius for the large disk would be entered as 12.5 and come out as 12.5 meters. This method avoids the tiny faces. You’ll export an STL file for 3D printing and they are unitless. You’ll just tell the slicer software the units are millimeters when you import the STL.

You don’t have to be consistent but it does make things easier. I can think of some situations where different numbers of segments would create a mess. Working at the larger size will help with that. In my GIF at the end of my last post, the units are set to meters and the number of sides on the circle to 48 so all of the circles in the model have 48.

It’s definitely a good practice to use some multiple of 12 for the number of sides. This makes circles divisible by 2, 3, and 4.

I redid the Follow Me thing using 98 sides. Here’s the STL from the result.
Spindle.stl (131.1 KB)

I feel like I’m running before I’ve learned to walk.

I installed Solid Inspector2 and that gave me the option to clean up Internal Faces, so I clicked on"Fix" and that took care of that. When I run it again I get a reference to “Nested Instance” which I don’t understand but I think will be OK if I export it to a slicer program. but it still doesn’t show “solid” in entity info. Do I still have a problem?

I also tried recreating the object by drawing a cross-section profile and then using the follow-me tool to sweep a circle. I used meters as units instead of millimeters, and I drew on a rectangle that I had drawn on plane. The drawing went quite well but the bottom of the cylinder is still open ( the problem I originally had), and it still doesn’t show “solid” in entity info.Running Solid Inspector2 gave me references to “Surface Borders”, “Face Holes”, and “Nested Instances”. I think I’m still doing something wrong and have attached the skp file for this drawing.

spool pin profile follow me.skp (270.2 KB)

Thanks for all the help.

Your model is kind of odd. in the way it is modeled. I wonder how you drew the profile. The large disk is not included in the group and I wonder if you had the profile and the circle for the path attached to each other.

The lack of solidity is coming from the open face at the bottom and the rim of the circle. I suspect you didn’t select all of the geometry before making the face. You could delete the face skinning what should be the hole at the bottom as well as the line going to the cetner. Then draw a line or two between the inside and outside to fill the face that’s missing.

You’ll also need to reverse the faces so white faces are out. The face orientation is critical for most slicer software as it tells the software which side the printing material is on and which side is air.

I’ve made it solid for you. @DaveR has explained what the problems were. The bottom centre wasn’t closed, either. And there were several stray lines, which Solid Inspector2 was able to fix.

spool pin profile follow me.skp (258.2 KB)

It may be hard to 3Dprint, unless you use support under the large disk, or print in two parts - the part below the large disk, then from the disk upwards.

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When I first drew the profile and used the follow me tool, the bottom of the profile and the circle used for the follow me tool were in the same plane. I think you’re speculating that’s why the bottom was open.

I redrew the profile and made sure the circle was not touching the profile. That resulted in an “Everything is shiny” message from Solid Inspector2.

And now that I’ve got this far, I have to reconsider designing the model as a two piece unit that can be more easily 3D printed and then assembled as a one unit piece.

Thanks for all your help, I feel I’ve made great progress today, DaveR and john_mcclenahan

Yes. Follow Me is additive if there’s no exsiting geometry in the path. It’s subtractive if there is. Had you deleted the face of the circle first or put the circle below the profile as I showed, you would have ended up with a face on the bottom of the extruded shape.

Very good.

Two pieces might be a good idea for this.

I thought I’d show the end results of this exercise.

I drew this part in Sketchup and a friend with a 3D printer printed it for me. I ended up going with one piece construction.

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One suggestion for next time, printing them on their sides may have worked better for you. The support material would be easier to remove and clean up and the structure would be marginally stronger by not having a snap-able grain running across the thin section.

Well, it was difficult to remove the support material in this case.

I guess the decision process to build vertical or horizontal is made by the 3D printer and not in Sketchup.

Yes, the person physically doing the printing chooses the orientation of the model in the printer.
Finding the optimal position is quite important. Often it is better to print on the diagonal, so you don’t have a large flat surface stuck to the support raft. Of course different types of printers have different problem.

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Thanks for showing that, Terry. Were you able to try using them?

I haven’t tried them in operation yet but in the lower picture, the spool pin on the left seemed like it would work well.

The spool pin on the right had a little deformation on the end of the small tube, I guess where it was in contact with the printing plate, That little bit of shortness allows it to be levered out of the retaining hole too easily. I think that was a printing problem and not a drawing problem ( although I think the small tube could be drawn a little bit longer too)

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