Workflow advice on KiCad PCB to Fusion360 PCB component questions

[eepete]

I have a number of new PCBs that I have made and am testing now. A next step is coming up to speed on Fusion360. So far I have about 38 hours of “screen screaming” and 2 hours of actual work accomplished, but this is how coming up to speed with a new tool tends to go.
I’ve read a lot of threads, including:
“Library Management in KiCad Version 5” (am structuring things that way)
“How to share step 3D model with all the components on the PCB too?”

I have a lot of parts where I made the footprint (often a slight variation on the manufactures recommendation base on making small trial boards and reflowing parts onto the board). As such, I am looking for the 3D parts model. I am able to add in the 3D model for a given part for a given footprint using the footprint editor…

Here are my questions or assumptions that may need clarification:

1. I see both .stp/.step files and .wrl files as being supported in KiCad. Fusion360 seems to only like step files. Is KiCad inclined to perform better with one type vs. another ?

2. If I end up having to create 3D models in Fusion360, is that process units agnostic or should I always be in either imperial or metric units ?

3. Presumably the origin for any 3D model should be the center of the part, with pin 1 at the upper left so that things will align?

4. I was using the Library Loader with Mouser, but when I upgraded to the current version it has a 50-50 changes of working and crashes a lot. So now I’m thinking just find the 3D file and go with that. It seems the connector companies (CUI, Kycon, Keystone) do a better job of creating a 3D model than the chip manufactures. This is good becuase for the chassis, I am mainly concerned with getting the holes aligned with the connectors on the PCB. I don’t really care about the models being “artistic”/pretty, the main thing I’m looking for is when I export a 3D viewer board, I can then bring that into Fusion360 so I can create holes in the chassis that line up with connectors. Is this approach a good one ?

5. I have noticed that when I bring in a 3D model, such as a chip from TI, while the model looks OK and I can enter it as the model for a chip in the footprint editor, I can not see the model when I bring up the board in the 3D viewer. How to fix that ?

6. I’ve seen the StepUp software videos and discussions, but that seems very tied to the FreeCad program. Is there value to StepUp in my workflow with Fusion360 ?

7. I suspect a lot of the problems here come from having too many “standards” for 3D models. Then add in “best practices”/conventions for aligning/orienting 3D models to footprints. All my footprints are centered, pin 1 upper left. Is there a good solution for when the downloaded 3D models are aligned differently? I suspect I can bring them into Fusion360 and re-position them.

Enclosed is a picture of the 1st chassis I did as a learning curve for Fusion360. It’s a chassis for a PI 3 that can hold a 40mm fan. All the PCBs in this group are PI sized, it’s just a convenient size and I hope it makes the chassis design easier. This is a good example of what I’m trying to do with the PCBs I’ve made. Am working in KiCad V(5.1.5f)-3
The forums have great information but span a lot of time. I’m struggling with what the current state of the art is for all this.
TIA

[paulvdh]

Quite a lengthy post. Please number you questions so referring to them is easier.

The .WRL files have fancy colors and textures. This is especially clear on big electrolytic capacitors and LED’s. The STEP variants are better suited for exchange with CAD programs.

I think that the STEP files have the units embedded and you can use either metric or imperial. Usually it’s older file formats such as .DXF that do not have the units embedded and you have to specify them on import.

If you added the 3D model to a footprint, then KiCad should show it in the 3D viewer. You can also check (and modify) the links to the 3D files directly in the properties of a footprint in Pcbnew. If it does not show, then the most likely issue is the pathname. You should handle this with environment variables for “external libraries” or relative to your project root for models specific to your project.

For alignment of holes, I prefer to always place them on a 1mm grid in KiCad so they have nice round numbers. Maybe you can snap to the holes in the 3D model in your CAD program, but personally I always double check the actual numbers.

KiCad V5.1.5 is very old. V5.1.12 is the current stable version. Increments in the last number are almost all just bug fixes and upgrades are relatively safe. Why do you use such an old version?

[ppelleti]

@eepete

Presumably the origin for any 3D model should be the center of the part, with pin 1 at the upper left so that things will align?

For SMD parts, the origin is the center, but for THT parts, the origin is pin 1.

[paulvdh]

Those are true for the most parts but there are some exceptions. You can read more about these in the KiCad Library Convention

Full KLC

[ppelleti]

@paulvdh

You can read more about these in the KiCad Library Convention

That is what I linked to in my post, F6.2 and F7.2. If there are exceptions, I missed them, and pointing to the whole document doesn’t help me find them.

[eepete]

I’ve numbered the questions. In many senses, they are related but I wanted to be specific. I’ve numbered them, thank you for that suggestion.

OK on your reply, that will help. I’ll have to investigate further on why the 3D view did not show the 3D model, I did explicitly set it for a given footprint and it showed up in the footprint editor.

Sounds like the step files are the way to go w/r/t/ both 3D in KiCad and how Fusion360 works.

No good excuse for using old version, suspect just years of paranoia where sometimes an upgrade was exchanging the bugs you know for the bugs you don’t. I’m at a good break point, so I’ll upgrade. I’m going to give V6 a few months and then upgrade to that before starting the next board project.

[eepete]

I’ll be on the lookout for that one. I know I did not do that for the various through hole connectors I have. I can make corrected versions with a slightly different name for boards going forward without breaking boards that I’m debugging now.