FC v0.17dev: Part Design Next Usecases and Best practices

[donjan]

Not sure if anything can be done in the context of this thread, but I'd like to throw in a use case: working on a nanometre scale.

AFAICT FreeCAD is supposed to be scale agnostic, but there are several problems when designing models for nano devices.
1. As shown in my thread here, the sketcher seems to internally use a nanoscale offset for vertices and edges, which leads to selection problems (and weird workarounds).
2. Trying to draw a b-spline just fails: the vertices don't connect. Zooming back out and drawing a b-spline works fine. Dragging it closer and closer while zooming in will yield a nanoscale b-spline eventually, but it behaves erratically (suddenly degenerates into connected-line-segments depending on where you drag it's vertices, and the green "support" lines are going all over the place).
3. Many small issues with chamfers etc.

It seems this has not been considered/tested much so far. Sure, I can work with mm and tell the other programs down the pipeline to scale accordingly, but having everything in nm would be nice and proper.

[cox]

Not sure if anything can be done in the context of this thread, but I'd like to throw in a use case: working on a nanometre scale.

I do not believe that this thread is the correct place for this, to me it seams like a feature request and should probably be discussed in general discussion and be filed as a feature request in the bug tracker.

This thread is intended to help guide users when trying out the new development version and reduce confusion.

[industromatic]

I'm using
OS: Debian GNU/Linux 9.0 (stretch)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.11570 (Git)
Build type: Release
Branch: master
Hash: a68940340747d3f18818fc7b0bc72eb59e7a0f25
Python version: 2.7.13
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

and want to do a sweep of a face made in solvespace, exported as .step along a path in a sketch.
My goals are to design moldable part shapes with draft angles and fillets on inside corners.

Where should I read about these new terms like: facebinder shapebinder body.
they're new to me since my last freeCAD project a year ago. Meanwhile I'm using searches to hunt for forum entries like this one to read.

[jmaustpc]

shapebinder

that is a PartDesign tool in FreeCAD 0.17 and onwards.

This is a link to a sandbox page where some are beginning the wiki documentation for PartDesign in 0.17 and onwards. The link will take you to the part of the page talking about shapebinder. The documentation is still incomplete, but it might help.
https://www.freecadweb.org/wiki/Sandbox ... hapeBinder

facebinder

That is a DraftWB tool that has been in FreeCAD for a long time. You can read about it on the wiki

https://www.freecadweb.org/wiki/index.p ... Facebinder

body

A PartDesign body is a single solid created by all the objects and operations contained within it. It must be a single solid.

A PartDesign Part, is an object containing other objects, including Bodies but also anything else for example a mesh.

For example, think of a old chest, lets assume it has a base solid which is a hollowed out rectangular cuboid, then a lid, then a handle. In PartDesign you would have a
1) Part (the complete old chest)
under that you would have
......Body (the base hollowed out rectangular cuboid)
......Body001 (the lid)
......STL file (the handle) imported from a file provided by your supplier

[chrisb]

I wanted to play around with the model provided in another thread. At a certain state I had detached the revolution from the pad and wanted to reattach it. I know how to attach a sketch to face, but in this case I had to attach it to the XY plane. How do I do that? It works well on creation but I did not succeed in reattaching.

[NormandC]

I do not believe that this thread is the correct place for this

+1

donjan's reply has no place here, it does not even relate to PartDesignNext and is more of a general FreeCAD problem. And FYI the Sketcher is NOT part of PartDesign, it is a totally independent workbench even though up to 0.16 its toolbar was included in the PartDesign workbench, it's just for convenience.

I also believe that industromatic's questions and jmaustpc's reply have no place in this topic either. Besides, some answers for industromatic's questions could be found in the "Useful links" at the bottom of the very first post in this topic.

and want to do a sweep of a face made in solvespace, exported as .step along a path in a sketch.

You can't use an imported face for a sweep in PartDesignNext. You need to use Part Sweep instead.

This topic is in danger of becoming a total mess that has nothing to do anymore with its original goal with questions that should be in separate topics so they can be searched and found.

[NormandC]

I know how to attach a sketch to face, but in this case I had to attach it to the XY plane. How do I do that? It works well on creation but I did not succeed in reattaching.

It's the same thing as it's always been, just use Sketcher MapSketch but select the plane instead of a face. Make the Origin visible and select the plane in the 3D view, or select its label in the Model tree. Next you'll be asked the attachment mode, just select "FlatFace".

[chrisb]

It's the same thing as it's always been, just use Sketcher MapSketch but select the plane instead of a face.

That's what I did, but to no avail: The Sketch is always attached to the last object. As an example:

- I deleted Revolution and detached Sketch001
- I added another Sketch002 attached to a face of Pad
- Padded it to Pad001
- detached Sketch002; result: the dependency tree shows that there is still a connection left between the Pads
- Tried to attach Sketch001 to the XY plane as you said above and recreate the revolution; result: Revolution depends on Pad001 and not on Pad.

Bildschirmfoto 2017-07-20 um 17.31.33.png (33.9 KiB) Viewed 2428 times

OS: Mac OS X
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.11614 (Git)
Build type: Release
Branch: (HEAD detached at a8faef0)
Hash: a8faef009b2e146767da8310ccc596c7ee63bb83
Python version: 2.7.13
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.1.0
Locale: German/Germany (de_DE)

[NormandC]

The Sketch is always attached to the last object

IMHO it's working as intended. A feature is always linked to the one preceding it in the history, because by default, the "tip" is the last feature. Since you deleted Revolution, then created a new Pad, when recreating the Revolution, it is automatically added after Pad001.

If you want the new Revolution to be before Pad001, then you need to set the Body's tip to Pad. Right-click on Pad in the tree and select "Set tip". When creating your Revolution, it will now be placed directly under Pad.

Afterwards, you need to set the last feature in the tree as tip or every new element will be placed under Revolution rather than at the bottom of the Body tree. You can also check what the tip of the Body is in the Data tab. There's a button to edit the tip, but it opens an empty window with the only choice "None (Remove link)". This may be a bug.

[chrisb]

Thank you very much for the tip concerning the tip! I must have completely missed it's introduction.