3Ds max and STL file.

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Saamec
Posts: 157
Joined: Fri Jun 21, 2013 9:28 am

3Ds max and STL file.

Post by Saamec »

Draw a model using 3Ds max. Not all in their work use SolidWorks. This package is more oriented to the engineers. I started to use 3Ds max for a very long time, 6-7 years ago when drew models for games. Advantages, in my opinion, is that in 3Ds max, you can import models created in Zbrush. Zbrush allows you to "sculpt" model, just as you would work with clay. You can create different figurines. Then the whole thing import it in 3Ds max.
Working in 3Ds max and then trying to print the resulting model on Felix 2.0, I was faced with a significant problem - 3Ds max exported model STL are not properly maintained. The model was obtained with double vertices, edges, and the normal vector been deployed at some landfills. All this, while cutting the model, led to undesirable artifacts, which in turn negatively affected the quality of the printed model. But the solution to this problem is. Regardless, drew whether you model yourself, or imported in 3Ds max, you must convert it to an editable polygon model (Editable poly), after the end of the simulation we converted again into Editable Patch. The essence of the process in the following. Landfill model is represented as a rectangle, and print format STL contains information on triangles. So when you export 3Ds max recalculates the polygon mesh and brings it into triangles. This is the whole problem. Calculation is misspelled, and the more polygons and more complicated geometry, the more errors. Converting model Editable Patch we the easy way to re-render the polygon grid, then you can safely export your model to the STL file. In addition, 3Ds max modifier contains situated in the list of modifiers, STL check. This modifier searches for a double faces, vertices, and deployed vectors of normals.
If you have any questions, please write, I will answer to all. 8-)

satoer
Posts: 436
Joined: Mon Oct 01, 2012 8:00 pm
Location: Netherlands

Post by satoer »

Hi fellow 3D studio max user!

I also use 3D studio max for my designs (see Thingiverse in signature). I'm a motion graphic designer and I'm using 3D studio max for about 12 years now. It's really not aimed for industrial design, but its certainly not undoable. Key thing, is that you need to work really neat. everything you print needs to be one single objects without intersections.

My advice:
- First set the units right. Customize = units setup (I use metric millimeters) after that => System unit setup (I use 1 unit = 1 mm)
- Work neatly. the final object needs to be a single object without intersections from other objects. If you do have intersections you need to Boolean-merge them together. This sucks big-time, always try to overcome this situation. 3D max has two Boolean modifiers, and the both suck, and I need them both. If the pro-Boolean does not work, I try the other Boolean modifier.
- Always save a un-booleaned version of the object.
- If you do have intersections that are impossible to Boolean, try other slicers. Skeinforge won't work, but Slic3r has more respect for intersecting objects.
- Don't use the mirror function. I don't know why, but it will mess your model up. Even if it looks good in the viewport, it still has weird behavior in Repetier-Host. I've tried re-setting the normals, but still got problems. (haven't tried your convert to patch and convert to poly solution yet)
- use export and not " export as" to export as STL. You still can export only the selected object.
My Felix 1.5 printed designs on Thingiverse
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Saamec
Posts: 157
Joined: Fri Jun 21, 2013 9:28 am

Post by Saamec »

Totally agree with you, except for the mirrors. This function I have never had a failure. I do mirror already converted object into Editable Patch. May appear sometimes double edges, but it can be cured welding vertices, naturally within reasonable limits, so that the model does not lose the whole geometry.

satoer
Posts: 436
Joined: Mon Oct 01, 2012 8:00 pm
Location: Netherlands

Post by satoer »

Well... here's a quick test (using MAX 2013). made a simple cube, copied it, and mirrored it. exported to STL and imported into Repetier host:
mirrortest.jpg
As you can see, there not the same. The lightning is totally different. Although the normals are perfectly okay in 3D studio max, Repetier-host interpreted it as inverted or something. This basic example slices okay by the way. But more complex models did gave me problems.

The main problem is, that you can't see there's a problem in 3D studio max. You have to import it in Repetier-host to see it. If you mirror something in the beginning and spend hours modifying the model (maybe attach other models to it). The final model is corrupted without you knowing about it. So, I just don't use the mirror option.

[EDIT]
Just made a test: Made a box, copied it, mirrored it, converted it to editable patch, converted it to editable poly, import in to Repetier host: Same problems :(
My Felix 1.5 printed designs on Thingiverse
E3D V6 Hot end upgrade for your Felix
Tweezer bracket for your Felix
Led bar upgrade for your Felix

Lioric
Posts: 116
Joined: Wed Aug 15, 2012 1:13 am

Post by Lioric »

Yes, satoer is right. It probably is better to don't use mirroring option when modeling. What mirroring does is actually creating a mirror matrix (the vertices data is not really modified) and it is up to the mesh processing application (when creating the STL) to correctly interpret that matrix.

I'm not really into slicers, and I'm not really interested on them (so I haven't reviewed their code) but to be on the safe side, the objects must be very clean (specially as different slicers interpret mesh features different) and avoiding mirroring is part of a clean mesh.

Saamec
Posts: 157
Joined: Fri Jun 21, 2013 9:28 am

Post by Saamec »

Very strange. Try to use a modifier Normal, he has to align perpendicular. And still. I understand you export the STL both the object and the parent and the mirror. Try to export separately. Of course sometimes there are such errors, sometimes 1-2 normal deployed, but printing, ultimately, I have not seen much of a difference. Layers were correct.
You can, and ignore the mirror mode, but when the model is very complex, have a lot of details and polygons will be difficult to build manually mirror variant of the model. So for example I typed complex structure of gears and support beams bolted also printed. This design for the automation of manual scanner "David Laser Scaner Starter Kit". Just drive laser hands is tiring, and the process turns out long and quality. So I say that half of the details are mirrored. I use 3Ds max 2009. Tried the other version, but this one dearer and closer, already used to it.
Try to use in mirror mode select COPY, and then Put in the Editable poly, then into Editable Patch, and then analyze modifier STL check. I think your 3Dsmax wrong generates a mirror object. Very strange, I have it never happened.

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