Alibre tutorial

[nfk]

Hi,
I`ve spend a couple of hours looking for a post containing some Alibre modeling tutorials.
I remember reading the post a while back but now i`m unable to find it!
I`m a noob at cad software and i would like to give it another try.
Any of you remember reading that post? I will get peace of mind just by knowing it exists! i`m believing i imagine it and i`ll need to see the doctor..

Thanks for any pointers!

Norberto

 

[JorgensenSteam]

Norberto-

I put a little info on a Solidworks tutorial here:
http://www.homemodelenginemachinist.com/index.php?topic=14098.0

The concepts are the same.

I also have Alibre, and have used it some, though not as much as Solidworks.

It took me a long time to figure out 3D, but thanks to some of the HMEM guys, and a whole lot of head scratching, I finally figured it out.

I can talk you through Alibre if you want to learn.
It is not that difficult if someone talks you through it.

Pat J

 

[kjk]

Here's a suggestion: Pick an engine like one of Elmer's for which the plans are freely available and re-draw the engine in Alibre. Where you have trouble, post questions here. That way every one will know exactly what you are trying to draw and it will be easier to help you.

 

[JorgensenSteam]

I learned 2D CAD first, and had a hard time transitioning from 2D drawing to 3D modeling.

The things that confused me the most about learning 3D modeling were:

1. 2D CAD (computer-aided drafting) is the computer version of drawing on a piece of paper with a pencil. What you draw on the flat X-Y plane of the screen is what you see and what you get. You can draw any line or shape anywhere on the paper, and no line or shape has any relationship to anyother line or shape, each object can be moved independently of any other.
3D modeling is not so much drawing as it is machining. With 3D modeling, everything is generally related to everything else (parametric, or parameters related), and changing any part of a 3D model automatically propogated that change to any other part of the model. If you think in 3D, think of starting with a block of metal and either adding on other shapes, or cutting away other shapes. Don't think in terms of drawing lines when you are doing 3D.

2. I was very confused about the "sketch plane" in 3D, and why I had to jump on and off of various sketch planes, and when I should do this, how do I create sketch planes, where, etc. Why can't I see all the sketches on all the sketch planes all the time, etc.

3. Which commands do I use to construct what type of model? Which commands do not always work very well?

4. Having created a part as a model, how to I modify the part?

 

[JorgensenSteam]

I created a few parts in 3D for the HMEM Team Build No.5, and in the process created some documents to better understand the difference between 2D drafting and 3D modeling.

For 2D drafting, you are looking at a 3-dimensional object, and drawing the front, left, right, top, bottom, and sometimes isometric views of this object.

For 3D modeling, your are creating a 3-dimensional object, and then letting the program create the 2D front, left, right, top, bottom and isometric views.
For 3D modeling, any change to the model is automatically and instantly reflected in every related 2D view.
3D modeling can also create bill of materials.

Below are the comparison charts.

Pat J

 

[JorgensenSteam]

For 3D modeling, generally, you create one part at a time, and save one part at a time as a separate part file.

Once all of the individual parts have been created in "parts" files, then a new blank "assembly" file is created, and the parts you created are inserted into this assembly. This is the "bottom-up" approach, and is the approach that I use.
There is a "top-down" approach, but I have found that it can be tricky and sometimes counterproductive since changes to a part can have unexpected and unintended consequences.

Pat J

 

[JorgensenSteam]

I did a fairly in-depth tutorial on drawing the Bernay steam engine, and it is too long to copy here, but can be seen at this link:
http://www.classicsteamengineering.com/index.php?topic=344.0

The complete Bernay engine drawings are available on this forum in the download section.

As you can see in the Bernay tutorial, generally, you pick a sketch plane, sketch a basic shape, and then either extrude a boss or extrude a cut.

Sketch planes can be the standard "front, top, right side", or a custom created sketch plane that can be anywhere in space, and at any angle.

Pat J

 

[JorgensenSteam]

The purpose for jumping on and off various sketch planes can be a little tricky to understand, but I generally start drawing an object on the "front" plane, and use the 0,0,0 origin as the start point for the object.

I select the "front" sketch plane to tell the program that I want to draw a shape on that plane. Selecting the sketch plane basically allows you to draw lines and shapes on that plane only.
Once I have finished drawing the shape that I want to extrude, I have to jump off of the sketch plane so that I can tell the program which 3D commands I want to use with that sketch.
Once a shape has been extruded into a solid, then I select the next sketch plane that I want to draw on, say the "top" plane, jump to that plane, perhaps draw a circle in order to extrude a hole, jump off the sketch plane, and then use the 3D command to extrude a cut.

So jump onto a sketch plane to sketch a shape, and then jump off to extrude, cut etc. that shape.
The trick with 3D shapes is that they have to be completely closed figures, no open ends, gaps, or extra lines floating around. A square can have four lines only and they must tough each other. The biggest problem people sometimes have is open sketches.

Pat J

 

[nfk]

Hi,
Thanks for the tips and links!
I was thinking about alibre because i have access to a spare license from work but i think any cad software would be ok for my expectations.
I have a couple of my own designs on paper and my goal is to model those in 3D as an exercise. (i figured out most of the bugs the hard way)
Pat, i will search for a solidworks trial to start with your tutorial.
Yours was the one i was requesting but i believed it was for alibre... i`m having senior moments very often this days :

Norberto

 

[JorgensenSteam]

Norberto-

The commands used for Solidworks and Alibre are virtually identical, so a tutorial for either one should apply to the other. I have both, and they work the same.

Good luck, let me know if I can help you.

Pat J

Edit:
Here is the Team Build No.5 engine in 3D.
Note that when I began modeling this engine, I was not very good at 3D, so the first attempt at the flywheel is a good example of how not to draw a flywheel. The second method worked better.
http://www.classicsteamengineering.com/index.php?topic=272.0

The plans for the TB5 engine are also downloadable at the link listed in the HMEM TB5 section.

 

[nfk]

Nice
I`ll give it another try tonight, after the kids go sleep...
I`ll post here my progress and questions.

Thanks again!

 

[idahoan]

Alibre does offer some of their training videos for free; check out,
http://www.alibre.com/training_support/freealibrevideotraining.asp


Dave

 

[JorgensenSteam]

I went through a number of tutorials, and they helped some, but what they don't tell you is how to draw engines, flywheels, etc.

I have also found out that there are several ways to draw parts, and some work well, and some don't work so well when you start making modifications.

I have used the revolve shape feature, but then have problems with it later when I cut it. I have learned to avoid revolving shapes.

I have had good luck revolving cuts.

Pat J