Remnants from first solid

Technical Problems
1

Hi. Thank you for accepting me in your community.

I am fairly new to Sketchup and get by ok to be fair.

Recently I started to learn more complex designed. But when I’m subtracting a solid from another, part of the first solid stays back.

If I do simple 2 solid block, the process goes smoothly but when I choose the 2 complex design, this is when the trouble starts.

Any idea why and what could be doing this?

Thank you.

2

Share the .skp file so we can see what you are working with.

What version of SketchUp are you using? What operating system and graphics card? Please update and complete your forum profile.

3

Here is the file. Hope you can shed some lights.

Thank you.

4

You have to make your file accessible.

5

Thought I have hmm. Let me try again.

Try and access again please. Thank you.

6

It’s not fully clear what you are trying to accomplish from your file as the two solids contained in it are not intersecting, but I”m going to guess you are trying to subtract the threads from the cone to make female threads in the center of the cone?

A few thoughts:

  1. for actions like this it’s helpful to keep your objects aligned with the world axis. Working at center with the blue axis piercing the center of the circular object can make aligning solids easier. It’s possible to align them correctly without the axis but if they are the only things in the file, center is easier.
  2. Get used to pulling your circles out on a given axis. When you pull the circle shape radius out in a random direction the facets of the circle do not align with a given axis, which can make future operations more difficult. It’s good practice to pull your circle out with one of the three axis colors showing in bold as you pull, this makes a circle aligned to the axis. It’s not super relevant for this operation but can save you much headache in the future.
  3. You are working at a relatively small scale for SketchUp, your bolt shape with threads is about 11mm across, this makes the tiny faces that comprise the threads very small. This is likely the reason your solid tools actions are failing. Sketchup has a low end tolerance for edges to form faces around .001 of an inch. Points in the model that are in that small range are merged into a single point and faces around that point fail to form. This is commonly known as the “tiny face” or “tiny edge” limitation. So if your solid tools action creates faces in this tiny range it will have holes in the mesh, or leave remnants behind, or just fail to complete. The solution is to scale up the geometry. For example I scaled up both parts in your model by 100 and performed the solid tools subtract without problem. You can then scale the part back down by 100 to the original size as small geometry can exist in SketchUp once it’s formed. Another method of doing this to make your geometry into a component and then scale a second copy of the component and do the solid operation on the second component, those actions taken at the bigger scale will be reflected int he smaller component, this is commonly called the “Dave Method” after the great DaveR, :waving_hand: seach that in the forum for more in depth description.
  4. For you file since you are working in metric I would encourage you to simply work in M and treat them as MM. This is a very common practice that may users employ including myself with working on models intended for 3D printing. I have the model space units set to meters and I model as if they were millimeters. If I want somthing 11mm wide I simply put in 11 and the object comes out 11m wide in the model, and I know that is 11mm. If you need to you can scale the entire model down, or a copy of it by 100 when you are done. But, as .stl is a unitless format, if your are 3D printing there is no need to scale, simply output your .stl from the meters file and when the slicing software imports it will appear as MM as most slicers assume MM or can be set to import as such. Working in Meters as MM is a practice every person using SketchUp for 3D printing parts is well accustomed to.
  5. Get yourself the extension “solid inspector”, it’s very helpful.

10

7

Thank you for the reply mate. Appreciate it.

So the files were ok and it’s the technique that was wrong or did you modify them in anyway?

Anyway I don’t tend to scale model up because last time I tried, I was having some difficulty so gave up and ended up always using and working with the exact sizes.

Yeah you are right in thinking that I was trying to subtract the bolt/screw leaving me behind the thread.

anyway thank you again for your help.

So you think by scaling the 2 solid parts and try again will work?

8

yes, select both items, invoke the scale tool, grab one corner and begin a scale move outward. Let go of the mouse and type 100 enter. Use zoom extents to see the new geometry in your window, Then retry your operation.

9

What is the intent for your model when you have it finished? Are you going to 3D print it? Are the threads supposed tobe a standard size?

10

Yes my intent is for 3D printing it later. But I’m still not sure why it was not working.

I do have solid inspector and I did make sure that they’re no errors in the solid groups.

I’m still not sure about the technique to use here.

If I use M, then by importing it in slicer it’ll automatically convert it into mm?

also by using using the scale tool, I just type 100 which will be 100 times it’s original size and then later scale it it -100? is that correct?

So sorry about all this questions guys.

Thank you :folded_hands:

11

Make them each a component.

Move + Copy them to the side.

Scale the copies up x100.

Edit, intersect, solid tools, whatever you wish on the scaled up copies.

The original (small) components will show all the changes you make to the big copies.

When finished delete the big copies.

12

When I model for 3D printing I work with uints set to meters and model as if millimeters are meters. I find this easier than dealing with 100x scaling. This avoids issues with missing faces. There is no need to do any scaling of the model before exporting the .stl file. I just export the .stl using Model Units. When the file is imported into the slicer it comes in as millimeters so correctly sized. Here’s an example:

Screenshot - 10_2_2025 , 3_12_57 PM
Screenshot - 10_2_2025 , 3_12_57 PM901×1110 112 KB

Using the method described by @bmike also works and I often use it when the required result needs to be shown in real world dimensions as in hardware for furniture (drawer pulls, hinges, etc.) No real need to do that for 3D printing, though.

FWIW, if you plan to 3D print your screw and the “spool” and then assemble them, you need to either create a larger internal thread “cutter” or you’ll need a smaller diameter screw. If you are intending to use an off-the-shelf screw in your spool, you’ll want to make the cutter the right size and right pitch for the required internal threads.

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13

Will try your method soon.

But still not sure how to scale it back to original size after the modifications have been done.

I tried scaling it to 100 then tried -100 but didn’t work?

14

-100 is not the inverse of 100. You would need to use 0.01 if you want to scale down after scaling up by 100. (Basic math.)

If you do what I suggest there’s no need for scaling up or down.

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15

A lot of people seem to not know that stl files are unitless. That is, if file says a vertex is at (1.0,2.0,3.0) there is nothing in the file that says whether those are mm, m, feet, or furlongs.

SketchUp writes the values according to the model’s units and the slicer processes them according to its own units settings (typically mm). So if you model and export as meters but the slicer expects mm, you will get automatic scaling by 1/1000. You don’t have to scale down.

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16

After selecting the [Scale] tool (accelerator key [s] and starting to scale by dragging a corner handle:

Scale up by entering 100 [Enter] in the box bottom right.

Finish your operations

Scale down by invoking the [Scale] tool and start fragging a corner handle then enter 0,01 [Enter] in that box.

Entering -100 will make a mirror copy 100 times larger.

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