I'm working on a SketchUp drawing of a hub for my PEX Octopus project, see here. The goal is to make the device by 3D printing.

This is my first use of any 3D software and while I'm very handy with 2D drawing, it's been a steep learning curve. I feel like I'm getting very close but I'm stuck. I have overlapping solid objects that I would like to merge into a single solid object. You can see this as the lines (residual edges) in the center of the hub, see image of drawing.

I'm familiar with SketchUps solids tools, and I was able to use the Subtract tool to punch a hole through the middle of the hub (to spare plastic when printing). But the Union and Outer Shell tools do not perform as I expect. The lines don't go away and the shapes don' merge into one.

In the image you can see the hub (green), a mock piece of 5/8" PEX tubing (orange), and the white cylinder I used to punch the hole. I've also duplicated one of the 8 solids that, when rotated and copied, produced the 8-legged hub. You'll notice that the hole in the center - into which the PEX tubing will fit - extends from the cylindrical leg into the rectangular body of the hub.


The SketchUp file is attached

 

Hello,
I tried to fix your model but then it was easier to start from scratch.
All that I have done different is draw in 1000X bigger scale.
At the end you can scale back before export to STL.
It is a known Sketchup problem with small dimensions.
You can see reported distorted faces if you check your model with susolid
Hope this helps.

 

Very cool, thanks. I had read about the scaling thing. So if I need to print a 1/2" diameter circle, I should draw it at 500 inches and then, at the end, scale it down?

I've also read about adding faces to curved surfaces, and I've been doing that.

 

You can also choose different units like meters and at the end you don't have to scale it back ,because STL file does not include the unit information.
So it means that you can draw like 1 inch is 1 meter (or yard) because in STL file the information will be only 1.

 

You nailed it, Maldar. Using a larger scale did the trick. I repeated my drawing at 10 meters = 1 inch and then all the Solids functions worked as expected. I've got nice smooth (96 face) curves and one large hub solid. Very nice.

Are my next steps to: 1) scale it down to 1 meter = 1 inch and 2) export the STL file?

 

"Are my next steps to: 1) scale it down to 1 meter = 1 inch and 2) export the STL file?"

I would scale it 10x so 10m is 1m and then select m as unit when export to STL.
Then select inch as unit in your 3d printing software.
So at the end your model will be in inch as in reality.