Need Help with Modifying files

Hi, I’m really new to this and I’m doing a project that I need something changed and I have no clue how to do it. I’ve tried contacting the creator, but haven’t heard anything back.

This is the project:

I’ve been trying to figure out how to make the yellow and green part straight (no curves). I just need the the whole part straight and then curve at the top so the red part and blue part are just fine.


Have you tried Tinkercad (it’s free)? For something quick and dirty, i use that to hack an STL.


I have no clue what I’m doing. I’m new it took me forever to be able to learn how to print.

I’m guessing I need to find someone to modify the files?

I usually find it easier to redesign things like this from scratch. I find it too time-consuming to try to modify STL files. Fortunately for you, the creator has very generously included a .STEP version of the model. I had a quick look and it is very possible to manipulate the model the way you want. FreeCAD or Fusion 360 should be able to do it pretty easily. Other programs that can work with STEP files should work too.

I get that you may not have CAD skills, so that can be a hinderance. Perhaps you could post an drawing, with measurements of what you want.

TinkerCad ( is designed for kids and easy enough to hack things that even I can use it. If I understand correctly, you want to delete the green part and straighten the yellow part to look something like this:

[ATTACH=JSON]{“alt”:“Click image for larger version Name: TinkercadDuct2.jpg Views: 0 Size: 113.8 KB ID: 16499”,“data-align”:“none”,“data-attachmentid”:“16499”,“data-size”:“medium”}[/ATTACH]


I’ll have to give Tinkercad a try. I never worked with any kind of cad program. . I’m wanting the Green and Yellow part straight like your picture above but need the our bend gone also. The parts can only go together 1 way they have inter locking ends that are directional that’s why I needed both Yellow and Green parts totally straight.

A drawing with dimensions would help a lot.

All I have is the files I downloaded from that site. I really wouldn’t know how to even measure this because of the locking joints.

I meant a drawing of what it is you want, with dimensions showing size of each section. Forget for a moment the files you downloaded. Presumably you have a need for something specific. Draw that.

Ok. Let me explain what I’m trying to do it might help out. I made my own BedJet. A BedJet pushes air under your sheets to keep you cool just google it, but I made my own. I have a 4" Flex duct running up to this and it’s not long enough to make it to the top of the bed mattress. I need it about 28 to 30 in tall so I needed more pieces, but the project I found they interlock with each other and are curved. I’m attaching pictures of what I have. Note it’s about 6 inch wide and the opening is 1 1/2… What I need is the to add straight pieces to make it longer. I already JB welded this together. Not sure if that helps, but the pictures will show you what I have and you’ll understand what I’m trying to do.The reason it’s flat is to fit between the mattress and footboard.

FYI… In that guys print I’m using the Blue and Green parts for this

[ATTACH=JSON]{“alt”:“Click image for larger version Name: 20221209_145024.jpg Views: 0 Size: 2.74 MB ID: 16513”,“data-align”:“none”,“data-attachmentid”:“16513”,“data-size”:“medium”}[/ATTACH] [ATTACH=JSON]{“alt”:“Click image for larger version Name: 20221209_145034.jpg Views: 0 Size: 3.51 MB ID: 16514”,“data-align”:“none”,“data-attachmentid”:“16514”,“data-size”:“medium”}[/ATTACH]

Basically, you need to print the blue part and make red longer with the correct mating surface. You might have to break red into segments to make it printable. Looks straightforward in TinkerCAD. I should have some time tomorrow to mash something together tomorrow.


OK, here is the red segment cut to 100mm. I put the mating parts on both ends, so you can join as many together as you like. However, even better, you can use the slicer’s scaling feature to lengthen the segment in only the long direction.
[ATTACH=JSON]{“alt”:“Click image for larger version Name: image.png Views: 1 Size: 135.6 KB ID: 16520”,“data-align”:“none”,“data-attachmentid”:“16520”,“data-size”:“custom”,“height”:“217”,“title”:“image.png”,“width”:“349”}[/ATTACH]
BTW, this was really only possible because the creator was kind enough to upload the STEP version of the model.​

100mmSegment.stl (276 KB)

Thank You! I really appreciate this. I’ve been trying all these different programs, watching a lot of YouTube videos, but I just don’t understand how to do this stuff. I’m pretty new to this and I did buy the Creality 5 Pro. To me this is all confusing because I don’t understand CAD also not being good with math doesn’t help. I’m going to tinker in TinkerCAD and see if that program helps me better understand all this. Again… Thank You!!!

TinkerCAD’s Align and Workplane tools are powerful. TinkerCAD is not a replacement for a true CAD program (download and check out FreeCAD), but it works fine for simple things and hacking. I took a design for a cooling fan for one of my printers and adapted the STL (made taller and extended the opening closer to the printer nozzle) for use with a different hotend (E3Dv6) using only TinkerCAD.


I’ve watched videos on TC and it looks easy but every time I try it the easy seems to disappear. Just can’t wrap my head around that program. That’s like Onshape I could never really get a good handle on it either. Then I found Freecad and after I learned a little about it I was able to create things. Simple things at 1st but as I progressed I got have gotten better. Always learning something new in Freecad. Freecad can be intimidating but if you start by staying in the Part Design workbench you should get the hang of it. There are several good tutorial videos on YouTube about it. Joko Engineering Help & Mangojelly are my favorites.

It was like that with F360 for me. My biggest issue with FCAD is that it doesn’t number bodies consistently. It re-enumerates them every time it does a render. Since I design using very iterative process, it would change things I did way back, causing issues. F360 assigns a unique ID to each body and doesn’t change them.

I’m working on a project where the naming bug is driving me crazy. Every time I go and do an update things below it break that aren’t even related other than being part of the same model. I’ve lost count how many times I have redrawn it or parts or most of it. Blender has a CAD Sketcher add-on now that is in development and I’m considering trying it. Don’t like cloud CAD programs so that leaves some out.

Yea that is a pain and the Freecad developers are working on it, supposedly when v1.0 is released it will be fixed, not time frame though. I’ve looked at Fusion 360 but it’s Windows Mac only and I do all my design on Linux. I have a MacBook that I use for other things, maybe I need to convince the CFO that I need a new MacBook then I can use this one in the man cave. :slight_smile:

Checked and F360 doesn’t support MACOS Ventura yet so it won’t work on my MacBook.

I made a decision a couple of decades ago to concentrate on Windows. I refused to get locked in by Apple, and Linux/UNIX have never really gotten their act together (I mean, who really needs a gazillion flavors of an OS), so Windows it is. Fortunately, that means F360 is available to me. But, each to their own. I am not an evangelist for Windows – it just suits my needs. That said, I do run a Linux based edge router, but it’s a canned application, almost like an appliance.

For me it worked the other way around. I dropped Windows about 15 years ago. Linux Mint is my proper replacement as it operates on a logical level like Windows where needed. When it came to CAD I checked Fusion, but it

a) was a “free license” of a company, which always fires back at some point and already did with this application, twice.
b) also failed to run on Linux without using some emulation, so it was out.

FreeCAD back then was hell,but also more or less my only choice to get something with a stable future. With OpenSource and CloseSource Software the developer support is the only thing which can waste your invested learning time. Closed source software more than open source.

So I settled with FreeCAD and it was bad. So many bugs. But it got better and better. The worst bugs are still in there, but thankfully the RealThunder branch has all the missing fixes. A bonus of open source.

At one point in the future Fusion will cut a feature you want and you will “blackmailed” by the company in multiple ways. Pay money or stay with just.Step files. Pay money to get the features you want and more important: Pay money to keep the experience you build up over time. The latter is key here. They want young people to lean software, so when they get into companies, the companies will pay for software they need for even more money. The free community, which provided bug reports and did all the expensive testing for free, is left on the side walk in the future.

If Fusion or any other solution works for you, fine. Just keep in mind that all the models you made may not be under your control. They get stored in the cloud and when the service (web based CAD) is gone, everything is gone. If the company locks you out, everything is gone.

Sure it rarely happens that you need to revisit a model, but it happens. The part you made broke and before reprinting your want to improve it. e.g. fix the weak point it broke this time or add a feature idea. This may not be possible if the software is not under your control. You cannot backup an old version of Fusion or a web application. When using Fusion on Linux a backup is just a drag and drop, as the appimage file not even requires an installation. I can use any version I want ready to run on my desktop. If a new version has a bug, I delete the file and use the older one, until an update fixes that.

Speaking of operation systems. I mainly use MorphOS (, which I am also developing for. Linux and therefor CAD is only a byproduct dealed with VNC on my dual monitor MorphOS setup to “import” software currently not available for out operating system. On the bright side I can fix and enhance the entire system to my needs, while with Linux, Windows and Mac I have to take what I get.

Oh dear. Another book written :smiley: