3D Files - Materials - Manual


@Pdwhite sent the 3D files for the frame to me. They are *.step files which I converted into STL files.
I don’t know much about step files, but STL is a widely available and well know format, and I think there should be no disadvantage of having the files in STL format available (at least none that I know of).
Also, since the free and open source 3D Software Blender is the only one that I have some experience with, I am using it, even though it’s not a construction-software, for betting understanding which file does what.

Here’s a screenshot with three different views. Each file, as Paul sent it to me, is available once - however some of the files will need to be made several times, such as the arm and hinges.

Below is the corresponding list. Note, I also changed the name of the files a bit and added underscores to not have any space in the filenames.

No. | Filename old | Filename New | Material | Number of pieces needed

01 | Arm.step | arm.stl | Carbon | 8 pcs
02 | back main plate.step | back_main_plate.stl | Carbon | 1 pc
03 | botom leg hing.step | leg_lower_hinge.stl | anodized Aluminum red | 2 pcs
04 | front main plate.step | front_main_plate.stl | Carbon | 1 pc
05 | inside leg.step | inner_leg.stl | Carbon | 2 pcs
06 | left side hing.step | arm_hinge_left.stl | anodized Aluminum red | 4 pcs
07 | right side hing.step | arm_hinge_right.stl | anodized Aluminum red | 4 pcs
08 | main arm hing.step | arm_hinge_top.stl | anodized Aluminum red | 4 pcs
09 | nob.step | arm_hinge_lock_knob.stl | anodized Aluminum red | 4 pcs
10 | lower plate.step | lower_plate.stl | Carbon | 2 pcs
11 | motor mount.step | motor_mount.stl | Carbon | 4 pcs
12 | motor support plate.step | motor_support_plate.stl | Carbon | 4pcs
13 | outside leg.step | outer_leg.stl | Carbon | 2 pcs
14 | power switch bracket.step | power_switch_bracket.stl | Carbon | 1pc
15 | top leg hing.step | leg_upper_hinge.stl | anodized Aluminum red | 2 pcs
16 | tubing update 1 set.step | tubing_v2.stl | ? | 4 pcs
17 | v2 body attachment.step | body_gooseneck-bar_attachment_v2.stl | anodized Aluminum black | 2 pcs
18 | v2 retaining cap | gooseneck-bar-cap_v2.stl | anodized Aluminum black | 2 pcs
19 | v2 Gooseneck Bar.step | gooseneck-bar_v2.stl | anodized Aluminum black | 2 pcs

If Paul is okay with it, I can share the step or stl files as a zip file?

Tips and jigs for CNC machining of aluminum frame pieces

Its fine with me, go for it.


@Pdwhite I also have a few questions:

a) The carbon plates, what is their thickness? Any special specifications to this material?

b) the CNC milled and anodized aluminum parts, what are the material specs? any special alloy or special grade?

c) how are the carbon parts connected with the aluminum hinges, with nuts and bolts, or are the holes threaded?

d) are there any additional spacers, nuts and washers used to to connect the two main (front and back) plates with each other, or are they “only” connected with the 4 arm hinges, the two leg hinges and the gooseneck bar attachment?

e) I think there is one piece missing: the connection between the arm and the tubing

f) how is the hinge itself held together? any special nuts and bolts?


Alright, thanks Paul, again. Here are the files: https://www.looxis.de/get/openppg_frame_parts.zip (7,7Mb)


Hey guys, instead of posting in the forum and folks losing track, I’ve posted these in the GitHub.


@etienne Any chance you could share the step files? Thanks.


@asteronaut sure, I indeed wanted to do that. here you go: https://www.looxis.de/get/openppg_frame_parts_step.zip

Would you care to let me know why you prefer to have the step files? I am curious what the advantage of this specific file format is.

@davek79 I only have a basic understanding of Github. as far as I know it’s mainly used for version control of code of any sort.
Do you think it’s possible to add the *.step version of the files additionally? they are not a newer or later version of the files, just a different format (the format I actually received from Paul).

Also, I missed to add a PDF file which shows the tubing profile, to the STL zip file download.
@davek79 can you add that to github as well? it’s included in the openppg_frame_parts_step.zip file.


@davek79 I noticed you added also the file “openppg.blend” to the github repository.
that’s actually the Blender Scene where I added all the files together and positioned them accordingly as it can be seen on my screenshot further up.

I did this, to better understand what is what and where it goes - is it wise to keep it there and in the *.blend format? I could convert it also into a STL file. Blender isn’t really a CAD/construction software … :slight_smile:

I once received a 3D-PDF file, where every part and screw was correctly positioned, named, specified and organised in layers, so that one could hide layers to really understand how everything is put together and what is what. It was for an open source 3D Printer, the mUVe.
Just checked it out again ( here it is: https://www.muve3d.net/downloads/DLP11.pdf ), and apparently that document was created with a software called SimLab Composer ( http://www.simlabcomposer.de/ )

Maybe someone who is better at this than me is able to create such a 3D PDF file ?

I think it would be really awesome to have something like that, which would also serve as a build manual.


Okay so thank you to @Pdwhite and @etienne for the step files. I had a quick attempt at assembling the parts on CAD and ran into some issues. I’m not sure why but there seems to be some misalignments with some of the holes. For example, the area where the arm connects to the main plates: the holes on the front main plate (distance between the two holes is 17.007 mm) do not match perfectly with the holes on the hinge brackets (distance between the two holes is 17.015 mm).

Any idea what the cause of this might be?


Thanks everyone for getting this up online.


I would say that this is neglectable tolerance? we’re talking about 0,007mm difference. A human hair has typically a diameter of 0,04 to 0,06 mm. so it’s virtually nothing. a small temperature change (and thus expanding or shrinking material, carbon fiber versus aluminum) will immediately compensate for that (or make it worse).


Usually the part models are 100% accurate and you set the tolerances in the part drawings. Here we have for example the leg hinges, they have no problems. They just snap together with main plates. And then we have the arm hinges and also the gooseneck-bar attachments that do not align with the holes on the main plates.

For me it’s fine, I can adjust the models to my liking but if someone starts watercutting the plates with DXFs from these files I think they might be getting it wrong.

Here’s a screenshot to illustrate the problem:


okay, that looks way more than 0,007mm though, I don’t recall the size of the gooseneck_body attachment piece, but i’d say this is like a 2 - 3 mm misalignment?
I think the issue is a small one, that can be corrected easily. However I only converted the files to STL and only “layouted” them like in the screenshot. I guess @Pdwhite needs to chime in here?


In fairness to @PDWhite-- he wasn’t quite ready to release and asked people to contact him directly if they were eager to start with what he has now. We probably shouldn’t be surprised if there are a few small issues?

I know you guys are excited to start and are just chatting, but wanted to point that out.


@quarksurfer nobody is blaming Paul!

@asteronaut, you said you’re putting the files together in a CAD software,
maybe you can correct the issues (I’d probably vote for repositioning/correcting the holes on the carbon fiber plate) and re-upload to github?


I’d rather wait what Paul has to say about this first. Obviously he’s already made the actual parts and they seem to fit together just fine so I assume the problem is somewhere else. Maybe I just messed up something or maybe the models he sent are wrong versions or something like that.


Github is very very useful for this stuff. Good choice!

Also, this applies to everyone, if you catch any other issues with the released files, consider opening up an issue in github using the issues tab. Perhaps Paul can keep an eye on issues opened up there so they can be kept track of? Once an issue is addressed and fixed, it can then be closed. In my opinion, it just helps with organization of all the potential bugs that need to be fixed.


Hi Paul @Pdwhite,
this is just a friendly reminder, that this needs your attention :slight_smile:

I also have the following questions, that others may have as well?

From looking at the pictures on the website, I can probably tell that
c) the screws/bolts probably fit into the (threaded) aluminum parts
d) yes, there are additional spacers

However maybe you can still clear things up and we can together update a 3D Drawing that would also serve as Manual.


Looking at the parts it seems that

a) the main plates and the lower plates are 2mm thick and all the others are 3mm.

b)It was listed on the specs that the aluminium is 7075 T6 grade.

c) the holes on the models are not threaded for some reason but I believe the holes on the actual parts are threaded.

d) there are spacers/standoffs between everything: 45mm on the arms, 35mm on the lower and main plates and 20mm on the legs.

e) yes that part is missing. Might be 3d-printed.

f)the hinge seems to be held together by a bolt.

Disclaimer:^this information might not be 100% accurate :slight_smile:


Yep thats basically 100% accurate. Holes are just threaded with there corresponding sizes (3mm hole is threaded M3). As far as a manual im going to be doing a build video for all of those who got the kits, and that will be available before kits are delivered. I just dont have the time now or is there a need now to prioritize the manual over other tasks, as no unbuilt kit have been delivered to people. So for a full manual your going to have to wait a bit.