Slicing stl model causes problems

I have a candle holder I was trying to make, and it looks fine in sketchup but when I go to slice it, it looks really weird. What do I need to do in order to fix it?


Reversed faces?

Not a solid perhaps?

Here’s the model. I thought that I had done everything right. I think I did invert the faces at one point b/c they were backwards
2x10 candle slender.stl (688.8 KB)

Upload the .skp file instead.

Here it is

2x10 candle slender.skp (1022.8 KB)

Reversed face on the end.

Internal faces indicating incorrect workflow.

Results of Solid Inspector 2.

I know we’ve gone over this several times before. You are trying to draw too much in 2D. Think about the way the thing will print. Draw the bottom face and extrude it up to the thickness in the bottom of the holes. Then add the circles for the holes, and extruded to full height.

Thanks. Is there any way to salvage it or do I have to start again? I got the alignment just right on this one

This is how I would redo it:


I seem to remember a similar candleholder from my early days in an architect’s office. It was made of some ceramic material. It might have been called “Brick sample”.

What’s going on with all this, are you deliberately spacing them differently?

The fact you have chosen to use 75 segments for your circles makes it difficult to align them and not being on axis makes it even more difficult.
GIF 8-06-2022 11-23-39 AM

Your circles should be an even number and pulled out on axis so you measure from vertex to vertex of flat to flat.

1 Like

Here it is with 50mm rad circles all spaced 32mm apart.
GIF 8-06-2022 11-32-42 AM

Cool. I hadn’t tried that. I am making my circles with 39mm between them. Is there a way to repeat so that I have to like you did in a single go so that they have 53mm from the other side as well?
2x10 candle slender.stl (688.8 KB)

Only if the ‘brick’ is 1457mm by 345mm.

Ok. Is there a way to shorten the side of the brick by 54mm? I tried pulling it in but it only took the top–Nevermind I think I figured that part out. Now I just need to pull it up?
2x10 candle slender.skp (177.8 KB)

You’re still not pulling your circles out on axis, which is making the segments split giving you 51 and an uneven circle.
You know the size of the circle and the distance you want it from the edge, so create guides to give you the centre of the circle then array from there.
Something like this.
Candle thing

If you don’t know what I mean by pulling circles on axis here is a gif showing what I mean.
Circles are made of flat segments, I have used 12 here to make it more obvious, so you have Points (vertices) and Flats (segments). If you don’t align them on an axis they can cause lots of problems, one of which is an issue in your model.
You can see the colour inference when the circle is ‘on axis’ and it goes black when ‘of axis’. In your model the vertices don’t line up so you get incorrect measurements. You aren’t measure either from point to point or flat to flat, but from an arbitrary point on a slightly skewed flat.
Off axis circle

I put in guides and tried adding the circle that way. I then pulled a circle along the guide. Is this correct?
2x10 candle slender2.skp (77.1 KB)

No. I’m not sure how to explain it better.

Look at your circle, the segments do not form a right angle when they cross the guideline, they are at a random angle, nor is the guide crossing at the midpoint of the segment.

See here how I keep the point of the circle on the guide/axis, and I can rotate the midpoint to the guide/axis if I want the flat side to be aligned to the axis.
GIF 8-06-2022 9-26-28 PM

I have no idea why it did that. I tried adding the circles again and it worked that time. I tried that copy method you did but it keeps telling me invalid distance
2x10 candle slender2.skp (78.5 KB)

Are you trying to type the distance and the number of times in the same go? Don’t.
Type the distance and hit enter, then type the number of times and x and hit enter.