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KeyboardWarrior
Posts: 478
Joined: Thu Jun 19, 2014 5:02 pm

Tip of the Day 32 - Self Intersecting Surfaces

Mon Jul 27, 2015 2:22 pm

Intro
Intersecting Surfaces are often problematic. The way to identify these issues is through going to Repair-->Identify Self Intersecting Surfaces. The model below is a good example of Intersecting Surfaces. Ideally, the CAD program exports a Sphere and a Cube without having the interior overlap highlighted in the picture below. Looking at the picture below, you can see that the term "Self-Intersecting Surfaces" starts to make sense, that these extra interior surfaces aren't necessary and will cause issue. In the case below, it would create a hollow region as shown in the second picture

Pictures
Image

Image

Identifying the Isssue
If your model is missing sections, or having issues when slicing, I recommend going to Repair-->Identify Self-Intersecting Surfaces which will check your model for issues. You can also use the Cross-Sectional tool in many cases to find these issues.

Solution
From there, if you have issues with your model, I would recommend using NetFabb or uploading your model to this website https://modelrepair.azurewebsites.net/ .

Solution 2
You can also go to the Advanced tab and enable "Merge all outlines into single solid model" for a model like this. For certain models, Merge all outlines into single solid model will cause issue though, in which case you would want to use a repair website or repair software.

Solution 3
Use the feature Mesh-->Separate Connected Surfaces feature. If the models are sliced in the same process, then they will be sliced together without issue. If they have overlap and you slice as multiple processes (for instance a process for the cube and a process for the sphere) that would would cause issue since you would have overlap in the area of intersecting surfaces.

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dkightley
Posts: 2095
Joined: Tue Mar 10, 2015 4:09 pm

Re: Tip of the Day 32 - Self Intersecting Surfaces

Mon Jul 27, 2015 3:17 pm

Another solution is to use the "Separate Connected Surfaces" function on the "Mesh" menu, which was new in v3.0.0...as documented here:
viewtopic.php?f=9&t=3096&start=4

The only disadvantage is that you end up with multiple entries in the models list....but that hasn't caused me any problems at all.
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

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KeyboardWarrior
Posts: 478
Joined: Thu Jun 19, 2014 5:02 pm

Re: Tip of the Day 32 - Self Intersecting Surfaces

Mon Jul 27, 2015 4:05 pm

dkightley wrote:Another solution is to use the "Separate Connected Surfaces" function on the "Mesh" menu, which was new in v3.0.0...as documented here:
viewtopic.php?f=9&t=3096&start=4

The only disadvantage is that you end up with multiple entries in the models list....but that hasn't caused me any problems at all.
Great catch! I added that as "Solution 3" to the post.

grue19
Posts: 43
Joined: Sun Jun 30, 2019 12:06 pm

Re: Tip of the Day 32 - Self Intersecting Surfaces

Tue Nov 26, 2019 7:44 pm

thank you for the separate meshes option! it appears to be working great for a pair of cowboy boots i'm printing with straps that are separate sub-objects embedded into the boot sides.

arhi
Posts: 406
Joined: Thu Oct 06, 2016 5:13 pm

Re: Tip of the Day 32 - Self Intersecting Surfaces

Tue Nov 26, 2019 10:56 pm

"Merge all outlines into single solid model" can mess up the object big time (inside holes will be gone)

if you have windows 10, loading STL into 3D Builder app (free with win10), go select all, edit / merge and then export the fixed object :)
gcodestat integrates with Simplify3D and allow you to
Calculate print time accurately (acceleration, max speed, junction deviation all taken into consideration)
Embed M117 codes into G-Code
Upload your G-Code directly to Octoprint
open source and unlicence

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