3D Modeling Tutorial – A Basic Approach

[PatJParticipant @patj87806]

Another feature of 3D modeling that I find extemely useful is the ability to change surfaces to translucent, so you can see through them, and see what is happening inside of a model, and verify that things are as you expect them to be.

Here is an example.

[PatJParticipant @patj87806]

Posted by Nicholas Wheeler 1 on 06/05/2022 21:08:25:

Pat, the other thing to do when that happens is to ask somebody competent for advice and actually listen to it. How many threads have we seen recently that have ended with the OP flouncing off after being told that his design/parts/approach is never going to work and starting over will save throwing more good resources after bad?

I am afraid I am guilty of just that sort of thing.

I am stubborn like a mule (according to my wife), and reluctant to change paths.

So for me, that would be the pot calling the kettle black, but I understand your point.

Edit:

My wife tells me that when I point a finger at someone else, there are three fingers pointing back at me, LOL.

.

Edited By PatJ on 06/05/2022 21:16:13

[PatJParticipant @patj87806]

I use colors much as they do in the pattern making world, but in my case it is more for emphasis and clarity.

I often use a light red color for surfaces such as drilled holes and bores that have to be machined.

I use pastels (correct term?) instead of the hard colors, and that seems to make a model more pleasing visually.

.

[PatJParticipant @patj87806]

I made up a few sketches to be able to visualize the differences between what I was doing with 2D CAD drafting, and what I was trying to do with 3D modeling.

This is the sketch for 2D CAD or manual drafting.

The process is to look at an object (engine), and then draw one part at a time in 2D.

If I change any 2D sketch, the part will not longer fit with the mating/adjacent part, unless I change the adjacent part.

I often would make a change to a 2D part, and then fail to get every view correctly updated, and fail to get the mating parts and views also changed correctly.

All of the 2D drawings are derived from the engine parts, and they are not linked in any way, and so are totally independent.

[PatJParticipant @patj87806]

With 3D modeling, the 2D drawings are automatically created (actually I guess manually created using drag and drop) from each 3D part.

Any change to the 3D part automatically changes/updates the 2D drawing.

Other benefits of making an individual 3D model for each part are that you can create exploded views, bill of materials, assemblies of complete engines, and use motion studies to verify conflicts as the engine is running virtually.

I have never gotten the bill of material to work very well, but that is a minor thing to me.

Edited By PatJ on 06/05/2022 21:30:32

[PatJParticipant @patj87806]

An example of an exploded view of a model.

[PatJParticipant @patj87806]

And perhaps the feature that really makes 3D modeling worth the time and effort to learn is the ability to 3D print patterns on a 3D printer.

This feature is worth its weight in gold and time (if your 3D printer works easily and consistently).

The patterns that are 3D printed are highly accurate, and you retain all of the fine details of a part.

A 3D printer will generally operate unattended (not always), and so most of the time that would have been spent manually making patterns is saved.

3D modeling / 3D printing is a 21st Century method of design and pattern making, in my opinion, and an extraordinarily powerful design tool.

 

 

 

Edited By PatJ on 06/05/2022 21:49:02

[PatJParticipant @patj87806]

It should be noted that I am not a spring chicken, I am very much old-school in most ways, I don't like computers or smart phones, I like cars that don't have any electronics in them, I have been using a stick welder for 59 years and I refuse to get one of those new fangled MIG or TIGG welders, I like to draw using either pencil, or Indian ink on vellum, etc.

Learning new computer programs was not easy for me.

So i guess it boils to to the fact that I am proof that you can indeed "Teach an old dog new tricks".

.

[PatJParticipant @patj87806]

Another neat thing that someone told be about (I forget who) is that 3D models can be downloaded for many parts and fasteners from McMaster Carr, such as these helical gears.

I can't necessarily edit these models, but I can import them and use them "as-is".

[Nigel Graham 2Participant @nigelgraham2]

Thank you for that sequence, PatJ.

Even on umpteenth sight I still find the mass of symbols and tools rather forbidding! I think one problem with texts and videos is that some at least assume prior knowledge of CAD principles. The quality of the specific packages' "Help" menu counts for a lot, too.

Other have told me I get into a pickle by trying to think 3D with a 2D mind. I can appreciate that does catch people out, but I disagree for me, because I set out intending to make a three-dimensional, not orthographic, representation; even if the generating sketches are plane figures. Just as I did when drawing in orthographic or isometric mode, manually.

The bigger trap I suggest is trying to jump in too deeply, too early.

'

I suppose what you show here, it will apply with appropriate local modifications to other CAD systems of that form?

You show making a solid cylinder by revolving a rectangle around one of its sides. Is it possible to offset it from the axis, or vice-versa, so revolving it to a tube without needing remove "material"?

You wondered if "flange" is the right term for what you added to the end of the shaft. Yes, it is!

'

"like climbing Everest…" To extend simile to stretched metaphor, I've no head for heights but am still somewhere in the Khumbu Icefall or perhaps the Western Cwm!

[Dave Smith 14Participant @davesmith14]

Nigel

Any 3D CAD system can create a hollow cylinder like you asked. Here is an example with flanges added at both ends as well. All done with a single 2D sketch which you can see in the picture.

[blowlampParticipant @blowlamp]

As Dave Smith shows, you can certainly make a hollow cylinder, as well as other shapes using the revolve function.

Martin.

[PatJParticipant @patj87806]

Posted by Nigel Graham 2 on 12/05/2022 22:37:55:

I suppose what you show here, it will apply with appropriate local modifications to other CAD systems of that form?

You show making a solid cylinder by revolving a rectangle around one of its sides. Is it possible to offset it from the axis, or vice-versa, so revolving it to a tube without needing remove "material"?

 

The "standard" 3D modeling programs I have seen all seem to work about the same.

I did use one program that was simplified for use as more of a generic building block type affair, but I think any standard 3D program will have the three planes, and will have commands that operate about the same way.

You can revolve a tube without removing material.

I repeat again, in spite of the multitude of toolbar buttons and pulldown menues/commands, I generally only use about 10 commands over and over again.

The multitude of commands in a 3D program is more about offering a complete set of features, and to some extent is a marketing tool, since reviews of 3D programs often list a matrix of features.

Never mind that you will only use 1% of the features; its about selling programs.

Its like buying a car.  The sales guy said "We have an add-on package for $5,000.00, and it has all these great features, including bluetooth".

I told him "I just want to put the key in the ignition, turn it, and have the car go when I need to go somewhere; I am not trying to impress the Joneses with my car appearance".

 

 

 

Edited By PatJ on 13/05/2022 02:54:25

[PatJParticipant @patj87806]

Here is another revolve example, which is a shaft for a sidelever engine from a large sidewheeler ship from 1840.

 

 

Edited By PatJ on 13/05/2022 02:58:07

[PatJParticipant @patj87806]

I have posted some screen captures of some of my 3D models in various places here, but them seem to be scattered about a bit.

I will post some here, to get most of them in one place.

This was I think the first engine I modeled in 3D, and I just sort of muddled through it, without really having a good sense about 3D modeling.

 

 

 

 

 

 

 

 

 

Edited By PatJ on 13/05/2022 03:14:51

[PatJParticipant @patj87806]

I am not sure which engine I modeled next.

I think it was a Stanley 20 hp engine, which I was able to get drawings from from the Stanley Museum.

[PatJParticipant @patj87806]

Then I dabbled with the Roberston semi-rotary.

[PatJParticipant @patj87806]

I played around with some Cretor's No. 6 configurations.

[PatJParticipant @patj87806]

A bottle engine

[PatJParticipant @patj87806]

I think next was a Dake.

My dad built a Dake, and so I created some accurate 2D drawings for a model Dake.

Then I decided to 3d model a Dake, which was a bit of a challenge.

I think this was one of my early 3D modeling attempts.

I was starting to understand 3D modeling much better at this point.

[PatJParticipant @patj87806]

Made a 3D model for a Galloway.

[PatJParticipant @patj87806]

Then a Soule Speedy Twin.

This engine was and is tricky.

 

 

Edited By PatJ on 13/05/2022 03:30:40

[PatJParticipant @patj87806]

Onwards to a sidelever engine (The Mississippi engine).

[PatJParticipant @patj87806]

The green twin, which I cast, to make a working engine.

[PatJParticipant @patj87806]

I always wanted a single-cylinder Frisco Standard, and so I am modeling one of those.

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