Create solid for 3d printing

[Bilan_Gumus]

Hi,

I’m trying to Boolean Union those 2 surfaces to create 1 solid surface. It doesn’t work, maybe because 1 surface is open ?

For mcneel.3dm (1.1 MB)

[encephalon]

use the command RemoveAllNakedMicroEdges on the upper surface shown on the image below. it will then join to a closed polysurface. but the entire thing will not simply boolean to the rest of the shoe, you have too many discrepancies for that.

[Bilan_Gumus]

Thanks! Well, if i have two closed surfaces overlapping each other, won’t the 3d printer count them as 1 solid anyway ? Or maybe i can use somethin like Meshmix to make 1 solid surface ? What strategy do you suggest ?

[JimCarruthers]

Depends on the slicer.

[theoutside (Kyle Houchens)]

shrinkwrap is your best friend when prepping parts for 3d printing.

[altamiro.aj]

Yes and no, I’ve encountered some surfaces so poorly modeled that shrinkwrap exploded the mesh in a weird way.

Managed to get around it by offsetting the mesh and using close holes, but lost a lot of detail in the process.

[BTH]

if you have overlapping solids, yes, most slicers will process the overlapping solids as a single object. in fact this is usually far easier and more reliable than trying to make one single polysurface if you are working with any remotely complex forms.

in addition, not all slicers process internal voids. the example in the file below shows an internal void where the purple volume is created by the adjacency of all the red volumes and is entirely contained between the red volumes.

solids and voids.3dm (303.7 KB)

if you export just the red volumes, some slicers will process this configuration as a single solid (eg: chitubox, zcorp slicer) and print the overall box with infill in both the purple and red volumes. some slicers will only process the red solids (eg: prusaslicer) and print support material in the purple volume.

for what looks like a shoe, it shouldn’t be a big deal, but in other models it might be significant, so see what your slicer does

[Bilan_Gumus]

What about Meshmixer ? Can i create 1 solid there before sending it to a slicer ?

[encephalon]

@theoutside

shrinkwrap is your best friend when prepping parts for 3d printing.

shrinkwrap is a nice tool but its not a universal remedy.

when the meshes/surfaces are not closed and the gaps too big you have to inflate the vertices cps instead which drastically deforms the entire geometry. specifically in this model i tried that to begin with, because it is oh so inviting but hell no that did not work here.

rather put some effort into fixing it instead

[theoutside (Kyle Houchens)]

this video covers a lot of different ways to close up a mesh, these techniques can be used in combination with shrinkwrap to get good results on even very messy meshes.

Rhino 8 - Watertight Mesh Repair

[BTH]

i’ve not used meshmixer in my process for printing. as long as you:

• make sure your polysurfaces overlap
• convert your polysurfaces to meshes
• export meshes as .stl

then the files are usually printable.

there are some weird moments in meshing offset surfaces like this:

Offset surface distorts geometry

take a look at these two blocks. they are for creating a magnetic lap joint for pieces of a topographic model. one hollow volume is generated by offsetting the curve and extruding (left), the other hollow volume is generated by offsetting the peg (right). offsetting the peg geometry creates a bad surface which creates a bad mesh later on in the process. i would usually scale down the topographic model to its size before doing adding joints, but due to project circumstances, the lap joints need …

but cross that bridge if you get to it.