Y Pipe Manifold

[ZooHead]

Happy New Year to all the Cheetah 3D forum members, and all 3D modelers out there.

I wanted to start the new year by sharpening and expanding my 3D
skills after finding a tutorial online for program called FreeCAD.

The object of the tutorial was to use a 2D engineering drawing to build a 3D object.
I didn’t care about the program so much, but I liked the object so I built it in Cheetah… a few times.

The original engineering drawing has two views, which don’t match each other.
That’s only a problem if you’re using the drawing as a guide, like with the Blueprint object in Cheetah 3D.
For a parametric CAD program, it’s all about the numbers. So if you built this in a CAD program,
you may not even notice if the drawing itself is wrong, as long as the numbers are correct.

I corrected the drawing so the two views match to make it easier to use in the Blueprint Object.

After building the object in Cheetah I decided I could use a CAD program.
So I figured I would see if it was a good companion program for Cheetah.
Now I have to figure out how to use FreeCAD. Once I get up to speed I'll report back...

 

[ZooHead]

I'm trying to work through some beginner tutorials but I am thwarted by the dreaded YouTube Blur.
FreeCAD has some small indicators around the cursor that look like smudges on the videos.

The second problem I'm having is the mouse settings that require pressing down on the scroll wheel button to rotate.
Who would design a button that rolls under your finger. Fine for clicking but not for click and drag.
Apparently Blender uses this configuration.
How do Blender users cope with that?

For anyone trying to build this in Cheetah, I made a gif showing one way to get started.

Tips: • Keep the cylinder at the default radius of 0.5 and scale and move the Blueprint Object to match.
• Use Ghosted or Wireframe Display with a Subdivision Modifier to get the scale correct.

 

[ZooHead]

Regarding the BLUR, I found the quality setting is super low by default.
Now it's set to the highest level and seems much better.

FreeCAD is the first program I've used that most of the
time you don't hold the shift key, or any other modifier key.
You just click on multiple things. Many things are click and then
drag as opposed to click and drag, which messes with my head.

Right now I'm building a bicycle stem. After that I might be ready to
try the manifold. I am exited to see how the mesh will look in Cheetah.

As far as building the manifold in Cheetah, there's something I don't like.
It's probably due to the triangles formed where the two halves join.
It's all in how the Subdivision Modifier deals with triangles on a curve.

The BULGE

To make a better connection, without a lot of fiddling, just turn the cylinder 45 degrees to start with.

In this situation an n-gon is better than two triangles.

 

[ZooHead]

Here's an example of the blurring of the cursor icons.
Screenshot of YouTube tutorial. I can't identify the tool by that icon.

But I'm making progress. Very powerful for a free cad program.

 

[Chris Heath]

Regarding the BLUR, I found the quality setting is super low by default.
Now it's set to the highest level and seems much better.

FreeCAD is the first program I've used that most of the
time you don't hold the shift key, or any other modifier key.
You just click on multiple things. Many things are click and then
drag as opposed to click and drag, which messes with my head.

I just downloaded FreeCAD yesterday.

I was about to mention resetting the Youtube video quality setting, but I see you found that. I find I have to reset the quality setting more and more these days.

I haven't had a proper play with FreeCAD, but I did notice selecting the mouse behaviour on installation. You can change it to match other apps. See below....

Here is the info. Hopefully you will find the mouse/modifier behaviour you are looking for.

Mouse navigation - FreeCAD Documentation

wiki.freecad.org

I think I'll watch a few FreeCAD videos and follow what you are doing here to get a feel for how it works before giving it a go.

 

[ZooHead]

Thanks Chris, I did notice that and couldn't find a setting that didn't use the scroll button.

In any case I think it's best to set it the same as the tutorial or it gets confusing, so I'll make it work.
The one I'm doing now is using the Blender mouse setting.

Here's the results so far- saved in obj format and rendered in Falcon.
Looks good but it's all triangles.

 

[ZooHead]

Not much editing to do in Cheetah but I can just go back to FreeCAD
and make changes like the beveled edges in this render.

 

[ZooHead]

Here's a link to the tutorial for this object.

 

[ZooHead]

And a look at the mesh.

 

[ZooHead]

OK this one feature makes it worth while to get FreeCAD even if you don't build anything with it.

During the tutorial for the bicycle stem we are instructed to load the Fasteners Workbench.
A workbench is a customized environment for specific tasks.

There is a full range of standard fasteners, at standard sizes.

I had to test the hardest type of screw to make within Cheetah... the Philips head wood screw.

Right out of the box the modeled screw looks really good, but not good enough for extreme closeups.
But with a little editing in Cheetah, it was easily improved.

 

[Swizl]

Wow, those are great ZooHead! I know how hard it can be to do hard surface modeling with rounded parts. I've been using FreeCAD for a long time. Mostly to convert 3d file formats for importing into C3d. There are a lot of great workbenches to use. The standard fasteners is great to use too. Most of the time I pull parts from the McMaster Carr website. Most parts have 2d and 3d files associated with them. If you didn't already know. https://www.mcmaster.com/

 

[ZooHead]

Thanks @Swizl, I haven't used a CAD program since Minicad first came out.
This is light years ahead of that. I can also see why you use it as a file converter.

There are so many formats in there, like a few STEP file formats which I hear are good for 3D printing.
I wish there was one with quads as opposed to triangles but that may be wishful thinking.

What do you think the best format for exporting to Cheetah is?

 

[Swizl]

Thanks @Swizl, I haven't used a CAD program since Minicad first came out.
This is light years ahead of that. I can also see why you use it as a file converter.

There are so many formats in there, like a few STEP file formats which I hear are good for 3D printing.
I wish there was one with quads as opposed to triangles but that may be wishful thinking.

What do you think the best format for exporting to Cheetah is?

I have very very basic CAD knowledge. I've used TurboCAD for some rudimentary 2d spline modifications when needed. Adobe Illustrator can open DWG/DXF files, but it really chokes a lot when I get big files from architects and engineers. So sometimes it quicker and easier to modify what I need before importing into Illustrator. I'd like to learn more of the way 3d CAD apps function. But it is harder to wrap my head around now that I'm more used to using Polygon modeling apps.

STEP or IGES are what I download from McMaster Carr. I may be wrong, but I think all CAD 3d file formats only support triangles, no quads. So there will always be some cleanup. Modo and Blender have a really good built-in tool for removing tris. There is also a script for C3d, but sometimes it bogs down with large dense meshes. Occasionally I also clean them up by hand when the other methods aren't working well.

My most used export format would be FBX, and then after that DAE. Although I do sometimes experiment if anything is odd with the mesh when I import into the target app. OBJ is also a good format, but doesn't import animations etc. If you are going from one CAD app to another, STL may be a better more universal format.

 

[ZooHead]

No FBX export in FreeCAD but there are some problems with OBJ and DAE.

I went through the bicycle stem tutorial a second
time and I had a lot more trouble than the first time.

I don't want to focus too much on FreeCAD here in the Cheetah 3D forum.
But I think the program is a great tool to use in conjunction with Cheetah.

This time through the tutorial I made some changes
and modifications to the stem design.

One of the modifications did not show up in the
OBJ or DAE file formats for some reason.

Even so It did give me a good framework to rebuild parts of the object in Cheetah.

 

[ZooHead]

Here's a comparison of the wireframes.

 

[ZooHead]

Here's something I don't think you can do in FreeCAD, at least not easily.

 

[ZooHead]

I have been working through a bunch of FreeCAD tutorials and building the objects,
the blue ones in the image, and experimenting with different export settings.

I got excited when I found an "allow quads" for the DAE format,
but I saw no quads generated so I gave that up for now.

The DAE export format settings have a choice of three "meshers"- Builtin, Mefisto and Netgen.
The Netgen mesher has even more settings including the allow quads checkbox.
I played with some of the settings a little but I'll have
to come back to when I figure out what I'm doing.

After building the blue objects in the image, and more, I felt it was time
to go solo and search for some mechanical engineering drawings.

The green object is one of those that was particularly hard to build.
It took two tries and three crashes but it finally came out great.

After all this I figured I could get through the Manifold tutorial by Computerized Engineering.

The tutorial is made by an Indian fellow who is sometimes hard to follow for a beginner,
he says "click here" a lot so you have to watch carefully a few times to get where he's clicking.

Tips: When he says press control, press command. He's probably on a windows machine.
When he switches to Draft Mode, he has like 7 snap setting on but doesn't tell you.

I'm glad I put myself through some prior training because even that skilled operator
could not achieve the Fillet in the Y crotch of the manifold. (see the right purple object)

The workaround was to export the object as a step file and
open it with another program, not available for the Mac,
and then load it back in and it would be fixed.

One YouTuber posted that you only need to export the file in step format
and load it right back in again so there was no need for the other program.