Problems with Part Design Additive Helix

[uofmrob]

Hi all,
I'm practicing some FreeCAD (0.20.1 AppImage in Linux Mint) by trying to render my mini basketball hoop. I'm using that as the net hook is a tricky shape. I'm having an issue using the additive helix in Part design. I have a sketch with a circular profile which I've offset from the XY plane. Then I have a Datum Line that I've referenced from the X axis and the offset where it needs to be. When I try to create the Additive Helix, I'm not getting any errors in the Report view, but it's not showing up. Could someone look at the file and see what I'm doing incorrectly?
Thanks!

Basketball Rim.FCStd

(20.64 KiB) Downloaded 11 times

[drmacro]

@uofmrob

When you create a PD Body, you have defined a container that will contain a single, solitary, cumulative solid. Each feature (Pad/Pocket/etc. operation) in the Body is cumulative (and the result of the feature is NOT an atomic solid). The result of each feature MUST result in a single solitary solid (that is an accumulation of it's predecessors).

The result of the AdditiveHelix does not touch the the slid created by the Rim Revolution operation. If you increase the radius of the circle in the sketch Rim Profile Sketch it works because the helix now results in a single solid.

Snip macro screenshot-f9778d.png (98.98 KiB) Viewed 602 times

[uofmrob]

Awesome, thanks so much for the rapid reply! I created a new Body and shifted the datum line and sketch over and it worked!

[drmacro]

Awesome, thanks so much for the rapid reply! I created a new Body and shifted the datum line and sketch over and it worked!

Hmm...now you have 2 Body's?

If so, that's not how it's supposed to work if you are build one "thing". If you created a new Body for the AdditiveHelix, you have 2 separate things, that happen to touch, but are not one object.

[uofmrob]

Yeah, I have two bodies at this point and was thinking I would make the net hook piece-wise (mirror the helix, then a pipe too join the two helices, and then two pipes on each side to join it to the rim) and then merge the hook pieces with a boolean, then a polar pattern and a final boolean to join them with the rim. What would be the best practice for making something like this? I've been using FreeCAD for around 5 years to make things for 3D printing, but it's all been pretty hacked together and I'm trying to up my skill level.

IMG_20221006_095216.jpg (147.46 KiB) Viewed 563 times

[uofmrob]

Well, I've got one of them, and it doesn't look too bad, but I don't think there's a way to make a polar pattern to get the other 7.

[uofmrob]

Well, not sure if this is the best way to do it, but I got it and certainly learned a lot in the process. The file is too big to upload, now, but I have a screenshot. I built the hook a bit at a time, then joined it to the rim with a boolean so that there was something to attach to with the polar patterns, and then ran a polar pattern for each part of the hook in the right order so that it was attaching to something. It's not an exact replication, but it was really just about learning how to use the pipes and helix tools better. Thanks for the help!

Screenshot from 2022-10-06 11-00-16.png (211.16 KiB) Viewed 516 times

[domad]

....

Hi uofmrob, greetings to the community!
..... you can do it with the Draft -> "Polar array" function

[uofmrob]

Thanks! That would have been more efficient.

[drmacro]

Just note, in the file provide by domad, there are two independent solids. Rim Body and Array.

If you want two solids, then that's ok.