Draw for 3D printing
SketchUp is a simple and versatile free software.
The SketchUp modeling method is not designed for 3D printing.
This software is very intuitive, but it is easy to run into some errors that prevent you from having the correct solids for 3D printing.
Drawing for 3D printing is different than creating templates for renderings or animations. There are some basic rules that must be respected so that the model can be produced.
Many of the most used software have been designed to create renderings, not for 3D printing: they can therefore generate objects at first sight perfect, but whose geometries contain errors.
In particular, these simple precautions must be taken into account:
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Volume
All objects must have a volume. Often drawing for renderings or animations we create surfaces without any thickness: with 3D printing we will create a solid object, real, which must therefore have a thickness, even minimal.
To give a volume to the surfaces it is sufficient to extrude them, so as to obtain solids
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Closed objects
Objects must be closed. Closed means to "tight seal" (watertight). If we imagine printing the object, we have to imagine it as if its volumes are solid, connected to each other.
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Manifoldo!
Objects must be manifold: in a nutshell it means that the geometries must have a inside it's a out without "holes". A mesh is said non-manifold when it has edges shared between more than two faces.
Errors can concern:
- faces locked in a volume
- double points
- edges
- separate volumes joined by a corner or a point
Each corner must have only two adjacent faces, no more and no less.
Points must belong to a single face. When two faces share a point, without having a common edge, then the point is non-manifold.
For example, when with SketchUp two faces are drawn and placed in an adjacent way, it is not said that the edges fit perfectly, so what on screen may seem like a solid is, in fact, a set of surfaces without volume.
To avoid problems like this it is always preferable to use the drawing tools dedicated to solids, or draw faces and then extrude them. To draw a cube, instead of drawing 6 faces and then placing them next to each other, it is advisable to draw a square and then extrude it.
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normal
All surfaces of your model must have the normals oriented in the right direction.
If your model contains normal inverted it can not be printed, because it is impossible to determine which is the "inside" and which the "outside" of the model.
In SketchUp it is easy to orient the normals and it is advisable to always do this before saving the model.
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Attention to the dimensions
You have to consider the maximum dimensions of your object, base, height, depth and their sum, x + y + z.
Each material has a different maximum printable size. For some materials there is also a minimum size.
Measure the thickness of the walls of your object: if the dimensions are lower than those guaranteed for the chosen material, your object could be very fragile or even break in production.
Find this information on the Technical details tab on the page of each 3D printing material.
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Before saving the model:
Right-click on one of the model's faces and choose from the menu Orient Faces
Even if it seems to have no effect, this simple step will give all the faces of the model the same orientation.
Now we can choose whether to save our file in .SKP format or export it in .DAE format
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Save in .SKP format
Menu File-> Save as ... and from the drop-down menu choose SketchUp version 8 (* .skp)
it is important to save the model as .skp version 8.
Done!
The unit of measurement chosen at the time of uploading to Vectorealism must correspond to the one set in the Sketchup template we used to model.
To check which templar you used just go to the menu Sketch-UP -> Preferences and from there select the card Template. The highlighted temple is the one in use.
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Export to .DAE format
Exporting to .DAE can help solve some non-manifold solid problems that can be found in .skp files.
From the menu File -> Export -> 3D Model ... select COLLADA File (* .dae)
Click on Options and make sure that they are only selected:
- Triangulate All Faces
- Preserve Component Hierarchies
- Export Texture Maps
Save the .dae file.
Done!
Once the .dae file has been loaded you will have to choose from the drop-down menu the inch unit of measurement to have the object of the desired dimensions.
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Most common errors
Does the model contain no information about the volumes?
If loading your .skp file on Vectorealism you will get this error message trying to export your model in .dae format and repeat the upload.
Is your model not manifold?
If after uploading to Vectorealism you receive an error message that warns you that your model is not manifold you can try to temporarily delete the larger faces of your model, to watch it from the inside: in the standard view, if you have not applied any color to your model, the inside faces must be celestial, the ones on the outside white / gray.
Also check that there are no more faces or lines.
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