Where to start with 3D models for custom parts?


#1

Where to start creating 3D models?
I looked around here on the forum a bit, but didn’t quite see what I’m looking for.
I just started using KiCAD and am slowly getting the hang on of it.
My questions involve 3D models to go with custom parts.
My first project includes 2 parts for which I had to create the schematic symbol and the footprint.
- a simple pad with a hole for connecting and soldering 18 gauge wire to exit the PCB and housing
- a Song Chuan 103T-1CH-S-12VDC dual relay

I would like to be able to add the 3D models for these items as well. In that vein I have a few questions:

  • Do I need to do anything for the hole and pad or will the copper and the hole show on the 3D model based on the footprint?
  • Where do I start with the model for the relay? Specifically:
    - I have access to Solidworks and Inventor and know how to use them, I am not asking how to do the actual modeling.
    - Do I need to create the model as one piece (a single part) out of one material, or can it be an assembly? (Plastic housing and metal pins.)
    - How do I go about getting the model into KiCAd once I have created it? Is there a step by step out there already?

I would like to add that I am not a coder and I am using the stable version of KiCAD.

I could download a free modeling software, but learning to use something that is very likely clunky in comparison seems counter productive since I have access to commercial software.

I have been using the CentextualElectronics “GettintToBlinky4.0” videos to teach myself how to use KiCAD and I am getting the hang of it pretty quickly.

Thanks for any tips and pointers!!!

I would love to upload my custom schematic symbols and footprints here after I get home if anyone wants to give them a look and give me some feedback…


#2

The hole, copper features, paste features and the shape of mask layer cutouts are generated automatically.

Get the datasheet of the part.
Then choose a 3d mcad program of your liking and create the main body. If you can do that maybe add some details. (example the pins)

I would suggest you use freecad with the kicad step-up plugin

You only need to export the model as wrl. I don’t know if this can be done directly from solid works. But maybe export a step model (with colors) import that in freecad and use stepup to generate the correctly scaled wrl model.

You don’t need to set the colors to represent the colors in the final model. You can use distinctive colors for each part of the model and assign realistic colors during the export step of kicad stepup.

You can also use stepup to import the footprint and move the 3d model to the correct location.

In the footprint you need to set the 3d model path correctly. I would suggest you either use your own path variable to point to your personal 3d lib location or put your models to wherever KISYS3DMOD points to.

Path variables are managed in the main window -> preferences -> configure paths.
Using a path variable in the 3d model path is done by using the prefix ${VARIABLE_NAME}/lib_name.3dshapes/model_name.wrl
(I would suggest you use the same lib_name for the 3d models and the footprints. In most cases it makes sense that the model name is the same as the footprint name.)


#3

Thank you.

So, if I am understanding you correctly, I can model it as a single part from one block of material and change the colors of specific parts (housing and pins) when I import it into KiCAD rather than build the housing as one plastic part and the pins as a second metal part and create an assembly prior to exporting?

I am going to start by trying it out in Inventor first. Only reason is that the Inventor I have access to belongs to me and is on my personal workstation at my house, where as the Solidworks belongs to my company and is on my work computers.

I have no issue downloading free software to do the file conversions, I just didn’t want to have to learn to use yet another CAD software package. I get confused enough already going between Solidworks, Inventor, and Catia.


#4

It can be one solid. The assignment of colors can be done in freecad for each face of the solid separately. But this is very laborious.

If your software can assign different colors to different faces without the use of multiple solids then you can go this route.

Typically i create each “part” that should have a different color as a separate solid. I assign one color to each of these solids. And fuse these solids as the last step. (Stepup has a button for fusing multiple solids. It should preserve the colors of the faces of your solids. At least the faces that will exist after fusing the solid.)

Because the difference between different colors of a part might be quite subtle it might be better to use bright colors that do not really represent the realistic look during the modeling and import/export.

If you export your part as different solids in one step file you can use frecad to give each of these solids a random bright color. Simply right click on the solid and select assign random color. (Do this if your modeling software does not support step with colors or if it is hard to assign colors in your modeling software)

During the export step of kicad stepup you get asked for each color of the original model what color should be used in the wrl and step file that gets exported.

You can play around with the files on the packages3d-source repo to get a feel for the export process. I think the display models might be a good example.


#5

Thank you!
I will start by making two solids, a black plastic for the housing and a silver metal for the pins.
I will go from there and see if I can figure the rest out.
I appreciate the help!!!


#6

To follow up on what @LsDelancy stated. You should install two tools:

  1. FreeCAD
  2. @maui`s StepUP tool for KiCAD

Checkout the StepUP thread(s) here and the tool instructions. Once you have the part 3D model, StepUP will read in the KiCAD footprint file and the 3D step file and allow to to interactively align them in FreeCAD. Then, it will write the properly aligned and formatted models back out to your KiCAD library path for use.

I don`t draw models from scratch unless I have to. Here are the places I look:

I already see a few on GrabCad that may match your footprint.


#7

Be careful when using externally sourced 3d models. Always read the license they have. Most of them do not allow you to share the models with third parties. A lot of them do not allow the use for commercial use cases.


#8

Thanks to all!
You have given me a lot to check out and look in to!!!


#9

Yes, I did not mention this. The three links above have similar in licensing. Generally, you can use the models for your own projects, but may not redistribute them (i.e. don’t submit them back to be placed in the KiCAD library) as @Rene_Poschl has pointed out.

Many are produced by the part vendor themselves to encourage use of their parts commercially. May times you may find the vendor has a model along with its datasheet for download. Again, free to use commercially on your product, but you may not redistribute.


#10

Interesting.
I couldn’t find anything on the manufacturer’s website.
I also can’t access Grab CAD here at work.
But, I’ll check it when I get home.
The actual generating of the 3D model(s) in Inventor would realistically take me less than 30 minutes, but the import process may very well turn out to be more demanding! LOL
If I can’t find a model I’ll be more than happy to share whatever I create here.


#11

please have a look at here

particularly Align Parts and User’s video tutorial…

there is a new Gui I forgot to mention

hoping this will help :smiley:
Maurice


#12

Thank you again!

I’m leaving the office in 10 minutes and can’t wait to get home, knock out the “honey do’s” and get on the laptop!


#13

For Inventor based modelling the orientation that gives you placement at 0,0,0 without any further messing is like this (1mm in Inventor = 1mm in KiCAD):

As per image, you need to create the parts as one continuous piece.
Materials can be assigned to features or even faces - only color and shininess info will make it though, no textures.

If you want opaque parts you have to get creative (search forums for my posts on this) as Inventor (tested up to 2015) can only handle this kind of setting per part and not per feature/face.

For direct use in KiCAD you use export as STEP format, like this:

Be aware that if you share your STEP file there will be information about you in them. I run mine past a FreeCAD script that @maui made to get usage license information in there and my personal info out of there.

PS: for DXF outlines for complicated pcb outlines I also posted stuff on the forums. Start with Sheet-Metal in that case and export the flattened part…


#14

That’s good stuff! Thank you, that info will certainly make getting through is faster!!!
I can’t wait to get in there and give it a go!
Now, if life would just quit getting in the way…


#15

With regard to accessing free 3D models I also wanted to point out that we provide access to free models through https://www.ultralibrarian.com/ and have a special page dedicated to KiCad file exports https://www.ultralibrarian.com/solutions/cad-vendors/kicad-pcb-libraries I hope you can find this information useful in your search for free CAD models.


#16

What is the license of the resulting files?
I assume the user can not share files downloaded from your webside. Otherwise your businessmodel will break down. (This would rule out the use of your stuff for any open source project. It does not rule out the use of these files by a kicad user creating a closed source project.)


#17

Generally you are not allowed to redistribute the parts you download; however, you may redistribute your designs, and your designs can have our parts in them, so I don’t think there’s an issue creating open source projects with our parts. With regard to sharing downloaded files, there’s no point in sharing the parts since anyone can go get their own, but we’re really not worried about what most people do with the parts they download. Our main concern is that someone is not building their own library for redistribution.


#18

Well no, because I can take parts out of an Open Source project and redistribute them. With your parts, I couldn’t do that.

Considering that your license agreement threatens to sue users who break the agreement, it is irresponsible to suggest people use your parts in ways not compatible with the agreement.

There is a point, which is that it is very tedious downloading individual files. In KiCad, it would be much more convenient to have a footprint library hosted on github for example.


#19

I tried two parts and just got directed to a page that links to retailers. No models included. Won’t be bookmarking and using the site at all.


#20

There is also the 15 downloads a week limit. (Might seem a lot but this is used up quite fast.)

Just to be clear: Nobody is complaining that you offer this service. But be up front what the exact terms of your license are.
And make sure you understand them before telling us it is ok to use something in an open source project.
There is a difference between one employee of a company promises that it is tolerated to use something in an open source project compared to it is explicitly allowed by the license.
A non binding promise can be broken. This might happen if your company is bought by someone who does not like open source for example.