Changing pocket or pad size leads to broken constraints

[citrullin]

This is a behaviour I recognized over the while with FreeCAD. It's pretty annoying.
When you change the height or depth of a pad or pocket, it breaks other sketches. It doesn't even matter, if they reference the pocket or pad.
It can be totally irrelevant for the other sketch, but for whatever weird reason it breaks.
If there is a log I can share it next time I run into it.
I am on version 0.20.1

[drmacro]

It is probably the "weird" and well documented Topological Naming Problem.

See here for more details: https://wiki.freecadweb.org/Topological_naming_problem

Note: this link explains how to use Datum planes to minimize TNP. But, IMO, it does not make blatantly obvious that the Datum MUST NOT be attached to generated geometry. It does indeed state during the discussion that the Datum should be attached to base planes and the Attachment offset used. But, many readers miss this point.

In addition, sketches can be attached and offset from base planes in the same manor. So, in most cases the Datum is redundant or superfluous.

[citrullin]

It is probably the "weird" and well documented Topological Naming Problem.

See here for more details: https://wiki.freecadweb.org/Topological_naming_problem

Note: this link explains how to use Datum planes to minimize TNP. But, IMO, it does not make blatantly obvious that the Datum MUST NOT be attached to generated geometry. It does indeed state during the discussion that the Datum should be attached to base planes and the Attachment offset used. But, many readers miss this point.

In addition, sketches can be attached and offset from base planes in the same manor. So, in most cases the Datum is redundant or superfluous.

Thank you for the link. It's a managable problem.

[drmacro]

One thing that's not covered.

If, for example, you use an expression based on the Pad length to set the attachment of a subsequent sketch, then the sketch will "float" with changes in the Pad length.

[Aldineyer]

As a recent FreeCAD convert, I have the following forum topics on my reading list. I recall there was

• Topological naming problem wiki page
• Getting started wiki-page In my case migrating from Fusion 360 page linked to.

The following forum topics look promising but may require more time to digest than the wiki pages:

• TNP problem understanding how to get around it
• Need help learning correct workflow to prevent dependency hell - changing one thing breaks everything
• Simple question on recommended workflow (Caveat: 6 years old)

If @drmacro or someone else has recommendations for newer/better pages, I would be very happy to add them to my reading list.

[drmacro]

As a recent FreeCAD convert, I have the following forum topics on my reading list. I recall there was

• Topological naming problem wiki page
• Getting started wiki-page In my case migrating from Fusion 360 page linked to.

The following forum topics look promising but may require more time to digest than the wiki pages:

• TNP problem understanding how to get around it
• Need help learning correct workflow to prevent dependency hell - changing one thing breaks everything
• Simple question on recommended workflow (Caveat: 6 years old)

If @drmacro or someone else has recommendations for newer/better pages, I would be very happy to add them to my reading list.

The wiki Topo page is about the best. (noting the additional comments I made about it previously in this thread) Videos on Topo on YouTube are typically not so good.

As for moving from 360, JOKO engineering has one that many claim to be helpful.

IMO, the best way is to pretend you don't know 360 and actually work through the two beginners series offered by MangoJelly on YouTube. Actually work through them and understand what is actually happening. Taking note of the tidbits he injects along the way that are just general usage.

[Aldineyer]

As a recent FreeCAD convert, I have the following forum topics on my reading list. I recall there was

• Topological naming problem wiki page
• Getting started wiki-page In my case migrating from Fusion 360 page linked to.

The following forum topics look promising but may require more time to digest than the wiki pages:

• TNP problem understanding how to get around it
• Need help learning correct workflow to prevent dependency hell - changing one thing breaks everything
• Simple question on recommended workflow (Caveat: 6 years old)

If @drmacro or someone else has recommendations for newer/better pages, I would be very happy to add them to my reading list.

The wiki Topo page is about the best. (noting the additional comments I made about it previously in this thread) Videos on Topo on YouTube are typically not so good.

As for moving from 360, JOKO engineering has one that many claim to be helpful.

IMO, the best way is to pretend you don't know 360 and actually work through the two beginners series offered by MangoJelly on YouTube. Actually work through them and understand what is actually happening. Taking note of the tidbits he injects along the way that are just general usage.

I recall watching a "tutorial" on CFD/FEM in FreeCAD from JOKO engineering, and as I recall it, I found it to be good. The following sounds like the video you mentioned. Make a Compressor: FreeCAD and Fusion 360- A Comparison |JOKO ENGINEERING|

The content over at FreeCAD Academy by @flowwie is of high quality since it's already gone through beta in German.

The FreeCAD 0.20 For Beginners playlist from MangoJelly Solutions looks very useful as well.

As you say, it is helpful to approach anything new and unfamiliar with an open frame of mind. Over the years, I've tried not to dig myself into a pit and only be able to do something with a single tool.