How do I edit an existing .stl file?  

RE: How do I edit an existing .stl file?

You can pull an STL into a 3D CAD  program, but easiest is to find or create a source file yourself. Lots of prints on Thingiverse or PrusaPrinter.org include source files in Fusion 360, OpenSCAD, or a universal STEP format. Those are easy to read into the CAD program of our choice -- FreeCAD is popular, Fusion 360 and Blender are the big dogs -- and modify them yourself.

RE: How do I edit an existing .stl file?

OK thanks a lot. So it should be within my limited capabilities to say start off say with a modification of the original design's lettering? And then progress to adding features to the original design..

RE: How do I edit an existing .stl file?

STL files are unstructured "triangle soup" data — they don't have any "parameters" that you can adjust or any high level structure like "this is a cylinder". They only contain the coordinates defining the surfaces of the object at individual points.

That doesn't mean you can't modify a STL, but it will be at the level of moving vertices around or performing unions and intersections, not "change the text" or "make this hole smaller".

RE: How do I edit an existing .stl file?

Posted by: @dai-wee-mike

OK thanks a lot. So it should be within my limited capabilities to say start off say with a modification of the original design's lettering? And then progress to adding features to the original design..

Yes, DEFINITELY try your hand at a bit of 3D design. It's not nearly as difficult as it was in the past. Rather than try to modify an STL, you may find it easier to just design something from scratch. Think of it like editing a PDF versus just retyping a document. The Prusa logo print is trivial. Check out TinkerCAD and FreeCAD. I don't use them, but both have reputations for ease-of-use. You want to design the part in a 3D CAD program, then export it to an STL for slicing and printing.

RE: How do I edit an existing .stl file?

Blender is great in editing mesh bodies, but it has a steep learning curve.

RE: How do I edit an existing .stl file?

OK great stuff guys.  I just DL'd Fusion 360 and I can see the ability is all there - very powerful - but I'm gonna need Ranger skills to scale the gradient required to just move an object around on the screen 😮   . The fun continues and this 3D printing world is a maze of fun rabbit holes to explore...

RE: How do I edit an existing .stl file?

@bobstro

Rather than try to modify an STL, you may find it easier to just design something from scratch.

This. In many cases it's easier to reimplement a design than to modify it. Take the lettering on an object as an example. Sounds trivial to replace an "a" with a "b". It's not, if all you have is the STL. As @kpreid pointed out, STLs are "triangle soup". Moving the triangles that make the "a" around to make a "b" is non-trivial. Even if you load the STL into TinkerCad, Fusion, etc, it's a lot of steps as these programs don't recognize what you clearly see as letters as separate objects -- to stick with this example. It's not impossible but requires work. Another idea is to contact the designer and see if they're willing to share the actual design files, such as a Fusion .f3d file with you or at least a .stp file.

RE: How do I edit an existing .stl file?

To get the most out of your 3d printer you should learn to model your own designs. Or like others said already, take something you downloaded as an example and  model it for your self again.

I do this purely as a hobby and never did any CAD before. I started with videos from Lars Christensen. In early videos he explained the basics the way I could follow it and these have helped me a lot.

You could start with his whistle video or any of his beginner videos.

Once you know some of the basics it is more fun to do. I remember trying a CAD program years ago and had no idea what to do on that black screen.

RE: How do I edit an existing .stl file?

@baklin

I will feed the kids and then start watching the videos you mention. I'm a visual kinda guy so they will be super helpful I'm sure. I can see that at least for me the ground up design and realization of a design will be where the satisfaction lies, as I'm sure it is with most of you...

RE: How do I edit an existing .stl file?

Posted by: @dai-wee-mike

Hello again all.

Not a total noob, but close. Have printed about 15 objects and now starting to get a little more adventurous. What I'd like to do is start editing/modifying existing print files but can't seem to find the way. For example, say I wanted to replace the letters on the Prusa Whistle object with my son's letters. How could I go about that? Is there a way to get into the source code and adjust the parameters? Many thanks, Mike  

With FreeCAD STL data can be converted into e.g. STEP data, which can then be further processed or modified on most CAD systems, of course also FreeCAD. FreeCAD is free and the handling is realtively fast to learn https://www.freecadweb.org/downloads.php

wbr,

Karl

RE: How do I edit an existing .stl file?

@baklin

+1 for Lars Christensen videos. I find most YouTube stuff to be crap but his videos are top notch. 

RE: How do I edit an existing .stl file?

Another upvote for Lars' videos. Great stuff and he's quite enthusiastic. It took me a while to get the hang of moving with the mouse. The day before my nice expensive SpaceMouse arrived, it clicked and I can't get used to the SpaceMouse. Still love using Fusion 360 though!

RE: How do I edit an existing .stl file?

Once you have a CAD program you cant edit an slt  file but you can modify one. I know that sounds odd but CAD programs allow to cut and add shapes to an object. That is you can or add cut a section out of the stl but the basic shape is a a dumb uneditable object which can have an excruciating number of polygons and cause slowing down.

You would still need to learn how to move and add elements so you might as well start the whistle from scratch to learn how to use the software.

RE: How do I edit an existing .stl file?

Microsoft 3D Builder is a free Windows app that lets you view, capture, personalize, repair, and print 3D models.

With 3d Builder you could Split (slice) the layer where the letters are inbeded, create a new layer and add your new letters.

I tried many of the CAD programs and was not able to overcome there learning curve. This one was easier but it took me several weeks/months to finally become useful. 

RE: How do I edit an existing .stl file?

Just my two cents.....First, let me say that learning to use a CAD program is essential to owning a 3D printer but it may also be beneficial to know how to modify an existing .stl file too. I do this using Fusion360, most recently to mod the filament sensor lever when I installed the MK3S+ conversion on my older printer. I'm not getting a solid flip from 0 to 1 when the filament is inserted. I believe I need a touch more length on the "flag" of the lever so modding the .stl seems the most expedient route.

In Fusion 360, insert the .stl file you wish to modify, click the gear in the lower right corner of the screen and select "do not capture design history", then right click on the object and select "mesh to brep". Now you have an object you can manipulate.

RE: How do I edit an existing .stl file?

Guys I’m grateful for all your feedback. Really. This is opening the box little by little. For me the programming goes hand in hand with the printing and I need to get a grip on both. Mastery may never come but small steps and small victories are enough right now. This stuff is as big as your imagination - very exciting times. 

F360 update

Fusion 360 has a new mesh workspace and can now convert mesh objects into optimized bodies.