3D-CAD Package Shootout – Cotton Reel Example

[blowlampParticipant @blowlamp]

This is MoI effort.

I didn't do the ends as I think this has been covered.

Martin.

 

 

Edited By blowlamp on 30/04/2022 17:46:56

[duncan webster 1Participant @duncanwebster1]

#2 son came round tonight. He is a bit of a CADS expert. Seems my cylinder model is all wrong, not constrained. Once I find out what that means (I have a fair idea!) I'll have another go.

[John McNamaraParticipant @johnmcnamara74883]

Hi All
Iron Twist Drawn using standard AutoCad
Method:
Drew a spline and dragged it into a 3D shape. A bit fiddly.
Extruded a circle over the spline line
Drew the base profile using a closed polyline.
Swept the base profile
Time about 20 minutes.

[SillyOldDufferModerator @sillyoldduffer]

Posted by duncan webster on 01/05/2022 00:37:47:

#2 son came round tonight. He is a bit of a CADS expert. Seems my cylinder model is all wrong, not constrained. Once I find out what that means (I have a fair idea!) I'll have another go.

I'm finding Solid Edge more sensitive to constraint problems than FreeCAD and Fusion. Partly because SE doesn't make missing constraints obvious, but mostly I suspect because the otherwise excellent Synchronous workflow doesn't encourage the user to apply them.

In 3D CAD, a constraint sets a dimension or coordinate to a fixed value, which helps the software by limiting the number of geometric solutions it has to calculate, and stops the user accidentally modifying bits of the model that should be anchored.

In this example, I've modelled a short rod, 20mm diameter, 30mm long. Solid Edge colour codes the dimensions:

• Blue means the dimension is unlocked, free to change, directly or indirectly. Really handy when a dimension changes automatically as the model takes shape, thoroughly confusing if it alters unexpectedly later as a side effect.
• Green means the dimension is being edited. In the example below, note the dialog box has a padlock button which can be used to lock or unlock the dimension. This is how dimensions are constrained.
• Locked dimensions cannot be moved accidentally. Solid Edge shows them in Red.

Next image shows the diameter of my rod model is constrained (20 in Red) but the length is not (30 in Blue). The model isn't fully constrained because I can alter the rod's length and also because it can move about – the rod is free to move in any direction. Again this is handy when the model is taking shape, but bad if it happens by accident.

Generally it's a good idea to lock and constrain as soon as that part of the design is confirmed. Don't go mad by prematurely locking too much though! Although constraining makes one sort of problem go away, it creates others to confuse beginners! If out of the blue an apparently straightforward operation behaves oddly, or won't work at all, it may be because an earlier constraint is non-obviously blocking it. Finding these in a big model can be tedious.

Learning FreeCAD taught me the importance of getting constraints 'just so'. At the Learner Driver stage, one is likely to create models that look OK but are internally flawed or hideously complicated. Caused by pressing buttons until something seems to work, which is liable to stack up weird or inconsistent geometries. Setting constraints tends to highlight mistakes and reduce nonsense structures. As a beginner I repeatedly crashed FreeCAD, Fusion360 and Solid Edge. Now I sort of know what I'm doing, I rarely crash any of them.

Reckon I've spent nearly 20 hours learning Solid Edge so far. As General Orde Wingate told the Chindits on their way to operate in the jungle deep behind Japanese lines: the first 30 days of a long march are the worst.

Dave

[blowlampParticipant @blowlamp]

…As a beginner I repeatedly crashed FreeCAD, Fusion360 and Solid Edge. Now I sort of know what I'm doing, I rarely crash any of them…

Dave

Why don't you have a go at crashing MoI?

Martin.

[SillyOldDufferModerator @sillyoldduffer]

Posted by blowlamp on 01/05/2022 13:55:08:

…As a beginner I repeatedly crashed FreeCAD, Fusion360 and Solid Edge. Now I sort of know what I'm doing, I rarely crash any of them…

Dave

Why don't you have a go at crashing MoI?

Martin.

It's on my list!

Seriously though, I like the look of MOI and the videos I've seen suggest it might do the twisty thing without much fuss.

Dave

[lee websterParticipant @leewebster72680]

I think there is a way of telling Solid edge to show which geometry is under constrained, but I never got it to work properly. One thing that really put me off using it is the "tree" with the list of everything you've done. In FreeCAD and Design Spark this tree shows the steps for each body, and the steps can be collapsed to just the name of the body. Solid edge seems to want to show everything all the time. Am I missing something?

[blowlampParticipant @blowlamp]

Posted by SillyOldDuffer on 01/05/2022 16:45:51:

Posted by blowlamp on 01/05/2022 13:55:08:

…As a beginner I repeatedly crashed FreeCAD, Fusion360 and Solid Edge. Now I sort of know what I'm doing, I rarely crash any of them…

Dave

Why don't you have a go at crashing MoI?

Martin.

It's on my list!

Seriously though, I like the look of MOI and the videos I've seen suggest it might do the twisty thing without much fuss.

Dave

Go back a page and you'll see I did just that.

Martin.

[SillyOldDufferModerator @sillyoldduffer]

Posted by blowlamp on 01/05/2022 17:48:46:

Posted by SillyOldDuffer on 01/05/2022 16:45:51:

Posted by blowlamp on 01/05/2022 13:55:08:

…As a beginner I repeatedly crashed FreeCAD, Fusion360 and Solid Edge. Now I sort of know what I'm doing, I rarely crash any of them…

Dave

Why don't you have a go at crashing MoI?

Martin.

It's on my list!

Seriously though, I like the look of MOI and the videos I've seen suggest it might do the twisty thing without much fuss.

Dave

Go back a page and you'll see I did just that.

Martin.

Now that's odd, either I've gone potty or your post wasn't there before. It is now. I've noticed before the forum or my browser sometimes fail to display a post that reappears later.

But yes, now I've watched it, you and MOI make twisting look easy!

Ta

Dave

[David-Clark 1Participant @david-clark1]

I have been following this with interest.

I think my choice will be Alibre.

I use an iPad Pro for everything at the moment.
I have a brand new laptop but can’t read the text or use the keyboard.

Has anyone used a Windows surface pro or similar computer with a touch screen to run Alibre.

I do have a Bluetooth keyboard and mouse.

[David JuppParticipant @davidjupp51506]

David – user feedback on Alibre with touch screen is that the touch screen doesn't work very well at all (I suspect that is true of many CAD systems). Alibre may cope better than some as in sketch mode figures are placed by click, release, move to next location click, release (mouse button is not held down whilst placing line, rectangle, circle…).

A mouse will be essential. For BT mouse double check if it can recognise using L+R buttons at the same time (many BT mice can't). Alibre does allow re-designation of mouse buttons, the default uses L+R buttons for rotate workspace.

Suggest taking a free trial of Alibre to check how it behaves with your proposed hardware.

[David-Clark 1Participant @david-clark1]

Thank you.

I wuss thinking of plugging a touch screen monitor into a newish laptop but don’t really want to buy the touch screen monitor unless I know it works with Alibre.

[David JuppParticipant @davidjupp51506]

Alibre is certainly designed around use with a mouse.

Users that have problems with mouse have used for example combination of trackball and a 3D controller. The 3D controller can be good for zoom/pan/rotate (and offloads those functions from the mouse), trackball (or mouse) is good for precise selection/positioning.

There will be a need to enter numbers – some have used a separate number keypad if main keyboard isn't good. A good on screen numpad emulator might be another option for use with touch screen.

That's potentially quite a few devices plugged in.

Hopefully a shop selling touch screen monitor would let you take in your own laptop to try out how the software and screen play together.

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