Noob help - 3D printing a sketchup model

Hi there!

First post and hope you guys can help me out. I’m a relative noob trying to create a file that can be printed on a 3D printer - I used the Solid Inspector 2 to determine if there were any issues and came up with “3 surface borders and 1659 internal face edges”. I’ve attached the file below in .skp format. Can any of you suggest what I should do next? I’d really appreciate any help! Thank you! L

Final Spikes Draft 17 - triple complete.skp (2.2 MB)

To start with, the cones are all inside out as evidenced by the blue faces. The cones have no thickness so they wouldn’t be printable. You need to give them thickness. How thick are you expecting the walls of the cones to be?

Here I’ve taken a stab at the wall thickness of the cones at 1.5 mm thick assuming they are supposed to be open on the bottom.

Notice that the blue back faces are on on the inside where they belong.

One way to model this would be to make individual cone cells as components that are solid. Then you can make an array of the cones and combine them with the Outer Shell tool. I made a quick array of just the largest cones to start.

Then I selected the components I wanted to replace with the smallest cones, found the smallest cone component in the In Model Components, right clicked on it and chose Replace Selected.

Then I did the same thing for the middle sized cones.

After Outer Shell and extending the base a bit with Push/Pull

Final detailing and copying to make the other three sections which makes a solid component.

There’s a single section of it in the foreground which is also a solid.

(Edit: My reply below was based on @DaveR’s initial, 1 paragraph reply before he edited it adding a LOT more detail!)

To continue where @DaveR left off …

Either give the cones some thickness OR close the openings on the bottom.As I can’t imagine what purpose this model has, I can’t guess at your intentions.

I’m a bit curious why you seem to have 3 nearly identical sections. As near as I can tell, if you added a chamfer on the ends matching the V grooves where the sections abut, you would then have 3 identical sections - which would then lend itself to modeling only 1 section, then duplicating it either in the model or, since you’ll be 3D printing, just print 3 copies simultaneously - most slicer software lets you do this.

And speaking of 3d printing, you really need to put what your modeling into a group or component. This is nearly essential for 3D printing since slicing software will do unpredictable things with models that aren’t solid. And to test solidity within SketchUp you need to look at the Entity Info while you have a group or component selected. There are lots of OTHER reasons to put parts into groups or components (just search the Forum), but this reason is specific to 3D printing.

And Dave’s advice about the reversed faces of the cones has particular importance in 3D printing. The orientation of the faces tells the slicer software what is “inside” and what is “outside” what you’re trying to print. With reversed faces, you’ll get unpredictable results.

Guys thank you so much for the quick and on the point feedback. My mind is blown. There is a lot to absorb.

  1. how can I add the thickness to the cones? 1.5mm is about right but I really want to learn how you did it! It’s not clear how the outer shell tool was used to make this happen. What I’m really trying to do is to be able to stack multiples of these elements together and be able to store them compactly in a box. In fact, the inner part of the cones should start from the bottom opening - since this will eventually be used to create a mold for plastics.

  2. @sjdorst - are you saying that once I’ve built the model, I should convert it all into a group? The 3 sections are not identical since the part will be built out of plastic and I want the ability to snap a section off if the user wants a smaller length.

Once again thank you! What a great welcome to the community!


OK. That explains the open bottoms. Never mind the idea of closing off the bottoms!

On your wanting snap off ability to shorten them, my idea of modeling them as a single short section, then printing them 3 at a time might still work, but would require experimentation with your slicer program and printer. To wit:

  • Will your slicer allow you to abut them on the printer bed?
  • Assuming it does, will the resulting part have the necessary strength when used as a whole, yet still provide the ease of “snapping” you want. (Actually, this should be tested in any case!)

In Repetier-Host you can add Parts together and use the Cura or Slic3r to slice them . . Had to do that with a Name tag of 2 colors . . Had the Base made as a part and the name as a second part so I could sell Custom Name tags . . So much for that Ideal ! . . Seems No one wants a Custom Name Tag . .

I didn’t use Outer Shell to give the cones thickness. I drew them that way. I started with a profile shape for the cone and added some for the base plate. This was drawn so the apex of the cone was at the center of a circle.

There are other ways to draw the cone, too.

Select the circle, get the Follow Me tool, click on the profile and the cone shape is made.

I drew a square centered on the bottom. Hit Ctrl after getting the Rectangle tool to draw the square from the center.

Push/Pull the face outside the square to get rid of the excess. Make sure you don’t have any holes and make the thing a component. It should be solid.

I repeated the process for the other two cones and made each of them a solid component.

As I described above, I made an array of just one size of cone. This was done with Move/Copy. Then I replaced some of the large cones with the middle sized ones and some others with the small cones. Note, the cone cells must be components for this to work. It does not work with groups.

After all of the cones were correctly sized, Outer Shell was used to combine them into a single entity.

You might find for small stuff destined for 3D printing it is better to work with units set to meters and just import the STL into the slicer with units set to millimeters.

Many slicers could handle printing the whole thing without actually combining them into a single solid entity. Here I’ve added the square holes at the corners and uploaded the STL to i.Materialise as a test.

The cool thing about leaving the cells as separate solid components is that you could quickly and easily replace some components with other ones to change the project.

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