Manipulating imported slt files?

darrin_jones

I realize now that I've put this in the wrong forum section. feel free to move it to questions, I don't know how...

ok I'm not sure what I'm asking... Here is what I want to do, I have imported an stl file (stormtrooper helmet from thingiverse) that I need to accurately resize for my daughters head. I can use the "scale" in the transform but that it isn't (or at least I don't know how) able to scale so that a specific dimension can be used. I.E. specific head width. with simpler models I just copy the shape creating a new part with the imported file as a template then dimension that. With my limited CAD skills I'm not able to use the imported Stormtrooper helmet as a template. 

again I don't know what question I need to ask here...
thanks

philip_thomas

@darrin_jones - thank you for your question. 

STL manipulation is something we get asked about from time to time.
While we would like to be all things to all people, we are maniacally focused on the workflows of pro users and have a long list of things we need to do for them. STL files are made from brep models (like Onshape, SolidWorks etc) and an Engineer would simply edit the brep and then re-export the STL.

There are free hobby grade STL editors and Autodesk has a fantastic suite of tools for this market - i would point you specifically to MeshMixer. http://www.meshmixer.com/

Good luck!

michael3424

Most slicers for 3D printers also let you scale the object before it is printed.

darrin_jones

philip_thomas said:

@darrin_jones - thank you for your question. 

STL manipulation is something we get asked about from time to time.
While we would like to be all things to all people, we are maniacally focused on the workflows of pro users and have a long list of things we need to do for them. STL files are made from brep models (like Onshape, SolidWorks etc) and an Engineer would simply edit the brep and then re-export the STL.

There are free hobby grade STL editors and Autodesk has a fantastic suite of tools for this market - i would point you specifically to MeshMixer. http://www.meshmixer.com/

Good luck!

Thanks Philip, I wasn’t asking for new functionality, just if it was something onshape already did and I just wasn’t aware of a setting or a workflow. I’ll move to one of the other programs

darrin_jones

michael3424 said:

Most slicers for 3D printers also let you scale the object before it is printed.

Thanks Michael, the slicer I use isn’t able to (or I’m unaware of) scale to a specific measurement. Which one do you use or can you recommend one that can scale by dimension rather than a percentage?
thanks

NeilCooke

@darrin_jones create a sketch of a line or circle with the exact measurements and use transform/scale to approximate the mesh to the sketch

philip_thomas

Well blow me over - did not know that we could scale STL!!!
@darrin_jones - I have some good news for you!!!
(thank you Neil)

Jake_Rosenfeld

@darrin_jones

If you share a link to your public document we can help you through the steps of how to scale to an exact size.

michael3424

darrin_jones said:

michael3424 said:

Most slicers for 3D printers also let you scale the object before it is printed.

Thanks Michael, the slicer I use isn’t able to (or I’m unaware of) scale to a specific measurement. Which one do you use or can you recommend one that can scale by dimension rather than a percentage?
thanks

Looks like you have a native Onshape solution now, per @philip_thomas post, but since you asked.  At the moment I use a proprietary slicer (Z-Suite for the Zortrax brand of 3D printers) but I'll probably be picking up a FormaLabs Form 2 SLA printer soon and I'm sure its (also proprietary) slicer allow one to scale the objects that are printed at slice time.  I just spot-checked Cura, Slic3r, and Simplify3D (all popular slicers) and they each seem to support scaling or re-sizing.

darrin_jones

NeilCooke said:

@darrin_jones create a sketch of a line or circle with the exact measurements and use transform/scale to approximate the mesh to the sketch

Funny you should say that Neil, I kinda had an "aha" moment this morning with much that same idea, though the inner circle Idea is, from my perspective, pretty damn clever. I could even make it roughly head shaped....

thanks Guys!

darrin_jones

michael3424 said:

darrin_jones said:

michael3424 said:

Most slicers for 3D printers also let you scale the object before it is printed.

Thanks Michael, the slicer I use isn’t able to (or I’m unaware of) scale to a specific measurement. Which one do you use or can you recommend one that can scale by dimension rather than a percentage?
thanks

Looks like you have a native Onshape solution now, per @philip_thomas post, but since you asked.  At the moment I use a proprietary slicer (Z-Suite for the Zortrax brand of 3D printers) but I'll probably be picking up a FormaLabs Form 2 SLA printer soon and I'm sure its (also proprietary) slicer allow one to scale the objects that are printed at slice time.  I just spot-checked Cura, Slic3r, and Simplify3D (all popular slicers) and they each seem to support scaling or re-sizing.

thanks Michael, I've been using a prusa printer which has a prusa version of slic3r, I'll look into the others you mention though.
Thanks

michael3424

@darrin_jones

It looks like the Prusa version of Slic3r does support scaling or re-sizing - see about 1/3 of the way down this page and look for "Scale" or scaling".

https://www.prusaprinters.org/slic3r-prusa-edition-beginners-guide/

nazim_zmirli

I've often wondered about this. Sofware I have builds STL from a model but won't go from an STL to a model. You can push and pull triangles around but not much more. I basically measure features and reproduce them in a fresh model. Any other methods?
Plex Lucky Patcher Kodi

apk_dodo

It looks like the Prusa version of Slic3r does support scaling or re-sizing - see about 1/3 of the way down this page and look for "Scale" or scaling".
You can check this out: http://apkdodo.com/

paul_britton

Freecad is the only thing I have found that can resolidify from an STL and then export out as a STEP file which allows me to use Onshape direct editing tools on the 3D object.
Fusion 360 may allow you to do similar, but I haven't looked into it far enough..

owen_sparks

paul_britton said:

Fusion 360 may allow you to do similar, but I haven't looked into it far enough..

I gave it a go, results were mixed.  Sometimes it took ages and ages, then reported an error.  Other times it took ages and ages, crashed and closed fusion.

I think the moral of the story is that stl files are a rough approximation of the original CAD, they are "lossy" to make.  A bit like a photocopy of a photocopy of a fax.  Unless it's critical to work from an STL just use them as a reference to build off to make new "clean" parametric CAD.

Owen S.

philip_thomas

What Owen said!!!! ^^^^  (for so many reasons).
Also - if you think of a casting, it might have what, 200 edges? 
A 'solidified' STL could have upwards of 500,000? 1,000,000? 
How well do you think that would perform in any system?
There are newer technologies coming, but for now, a mesh/cloud dataset should be for reference only.