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Top-Down design

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PaulProe

Senior Member
I grew up in my career with pencil & paper doing my design layouts with a parallel bar, then a drafting machine. Self-taught myself AutoCad and slowly transitioned my design work to digital. I am trying to convert my design work from 2D to 3D but keep falling back to 2D.

Is there a simple way to transition or any tips. I believe the best way is to do Top-Down, but struggle with the design process, or at least in the manner to which I am accustomed. You can't draw in assembly view so do you start with a 'new piece' and keep adding more? Sometimes your design doesn't have a place to start. You think you want a frame with members 24" apart but don't know till you get further into it, what size they will be. (Sorry, thinking out loud)

Does anyone have any tips on how to wrap your arms around this? Most of my work is automotive-related. I can easily design a bracket to hold x & y together at a given position. But when you have a blank sheet of 'screen' to design a frame . . . ?

Am I making it more complicated than it should be?

Thanks for any suggestions

Paul
 
wagnuts

wagnuts

Member
Hi Paul, nube here but this is what I've been doing lately: select any face or plane in the assembly workspace, and right click. at the top of the pop out is activate 2d sketch.
from there you can use project to sketch to create lines or refrence lines and points that follow the geometry of the parts you select.
 
wagnuts

wagnuts

Member
on the same sketch plane that you just opened you can insert a picture to trace if you are trying to match another shape.
 
HaroldL

HaroldL

Alibre Super User
In Top Down modeling you can sketch in the assembly view but when you start the assembly model you need to first cancel the Insert Part window. Then go to menu Insert>New Part and pick the plane you are going to sketch on. It may be that you need to create some new reference planes to sketch on for correct placement of the new part within the assembly workspace.

I think I would find it easier to start with individual parts and model them first then add them to an assembly. As @wagnuts mentioned, you can insert a picture to trace, if you have one, but you need to be editing a part model. IF you have a screen shot of your 2D drawings you could use them and adjust for the scale factor of the original drawing when inserting the image.
 
H-L-Smith

H-L-Smith

Senior Member
When you say, "automotive related", what kinds of things are we talking about, Paul? Depending on what kinds of things you typically create, I may have some ideas for you.

Lonnie
 
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PaulProe

Senior Member
Learned something new. Didn't know you could sketch in an assembly. Alibre, I know documentation is a BIG task, but it sure would be nice.

Lonnie, I have a side-hustle that does Cobra and GT restoration and replica parts.

Paul
 
bigseb

bigseb

Alibre Super User
Not really a fan of top-down design. You can it in Alibre although it's a bit clunky (not that other software does it better; they don't imo). Since I have a fair idea of how to proceed before I even start to design its easier to get the basic parts down and then refine them as I go along. Also not a fan of sketches in, say, Part A being derived from features in Part B. Assembly based sketches and constraints can just be a massive headache down the line.

As an alternative I would much rather use GPs to drive parts. GPs really open up your design capabilities a lot more than designing parts in an assembly workspace.
 
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sz0k30

Senior Member
I think I would find it easier to start with individual parts and model them first then add them to an assembly.[/QUOTE said:
While there are always exceptions, I think pretty much every experienced user will tell you this. So if you are a beginner you should listen to this good advise.
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