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Been a while since using Alibre, Attempting a new assembly and nothing but constraint problems

rmcard

Member
Trying to create an assembly for a fire pit gazebo using 6 x 6 posts and have started off creating a lot of planes and axis's so I can use the geometry of the assembly to bound parts and get compound cutting angles. Not working out of the box.

First off, my attempt to first create a part within the assembly was a non starter because all the assembly reference planes and axis I made went away when the assembly went into new part mode. That's probably just me not remembering how to make them visible because I do remember doing such things in the past.

My next attempt was to make a small coupon cross section of a 6 x 6 post I could then constrain into the assembly and proceed to edit it within the assembly so I could extrude it out to the various planes I created and then use other planes or solids to also subtract from it to get the various compound angles I'm looking for.

I started adding constraints to my little coupon which I thought were vary basic to lock it in 3 ways and I right off the bat starting getting swaths of them showing red highlights saying they were bad. And on my next re-attempt I got a mate constraint that highlighted green but the part plane chosen did not slide over to the assembly plane chosen and I could still move the back and forth in the constrained direction. Very frustrated and not happy.

The final straw was shutting Alibre down and upon restarting and getting back into the assembly, all the constraints were highlighted red again.
 

Attachments

  • Fir Pit Gazebo.AD_PKG
    93.2 KB · Views: 4

HaroldL

Alibre Super User
I checked the constraints on your assembly and found that by flipping Coincident (6) and (8) a couple of times I was able to get them to resolve. I was able to extrude the cross beam to the adjacent posts too. The issue now is that when you regenerate the assembly (F5) the cross beam flips to the opposite side.
Here's a video of my analysis:

and the package file
 

Attachments

  • New Assembly (1).AD_PKG
    98.6 KB · Views: 0
Last edited:

idslk

Alibre Super User
I changed one constraint from an plane to an axis. (and extruded the cross post and added the post to the pattern):

1655366027250.png

Assembly is stable and nothing flips :)

Regards
Stefan
 

rmcard

Member
Although I believe I am methodically and logically adding planes and axis's one upon another as well as following up with constraining parts to said constraints in similar fashion I must be breaking some cardinal rules on how to create planes and axis's or adding constraints to parts. Maybe a mix of both. Is it possible because some of the constraint geometry depends on features created from an array???

This is only the beginning of the assembly, I have a lot more features I am adding and I like this first part I where I was attempting to reference offsets from one plane to another so I can adjust positions of posts up, down, in and out there's going to be lot's more planes and axis's.

I know I have done this before in older versions of Alibre and I don't remember having such a rough time of it, has Alibre become more finicky with it now a more powerful feature rich program? It could also be just me being away from it for a while and being a bit rusty. I will go thru the responses and see if a light bulb clicks on in my head.
 
Hi Rmcard

Welcome to my nightmare, I have this same problem constantly.
The last 2 versions have been very bad at getting phantom constraint issue with parts added into large assemblies. You build the assembly constraining as you go with no problems only to reopen the same assembly the next week to a sea of Red constraints.

My investigations and experimenting concluded that using main assembly planes and individual part planes or surfaces can only stay correctly constrained if you use 2 plane to plane surface constraints and a 3rd Origin (point) to plane. This seems to stop the 3rd constraint from over constraining all 3 constraints.

Very frustrating I know and I have spent hours suppressing constraints from the bottom up identify the problem constraint.

90 % of the time its the 3rd constraint in a 3 way constrained part that is the problem

Hope this helps

Southernpedro
 

rmcard

Member
Ok, now I'm pissed.... I can somewhat understand (or maybe more accurately accept) having to rub my belly and pat my head to get some of these constraints to work but after again having my little coupon seize up on me after throwing more constraints at it (I did originally have some success changing a plane constraint to a point constraint) I totally DO NOT understand why the little sucker is still locked in place on my assembly after removing ALL associated constraints to it.

I'm officially not going to blow a gasket yet because I understand that version 25 is SUPPOSED to drop early this next week. If I still have problems I'll attempt one or two wipes and clean installs. After that it may come to a rather tense WTF discussion with Alibre support.
 

Attachments

  • Fir Pit Gazebo 2.AD_PKG
    92.7 KB · Views: 4

DavidJ

Alibre Super User
Staff member
Inter-design relation is holding your part fixed. If you remove that, you can move it around.
 

rmcard

Member
My bad, that IDR was from my first attempt to extrude out my part but it didn't give me the result I wanted so I deleted the extrusion assuming all associations would go away with the deletion. I was wrong.
 
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