Parametric Blocks saved without Constraints (?)

Piekaro

Hallo everyone,

I hav a huge problem with parametric blocks, which I cannot understand.
I am modelling elements and apply constraints. When I check it - klick "Animate" - everything looks perfectly fine. So I save the file.
When I open it again, almost everything is not working. Surfaces in the Contstaints are random, not those which I saved few seconds ago.
And now the most incredible thing - when I insert the same block to a project, everything is ok...

I have no idea what I am doing wrong, but I need to know it, because in the future I have to remodel those parametric blocks.

Any suggestions?

RSW

@Piekaro Do you have an example file you could share?
It looks like a constraint that behaves a bit different from expected or it might be a bug somewhere that shows in your specific case.

With 3D constraints I sometimes run into this as well because constraints behaviour is not always as expected, partly because there is sometimes a difference in the order in which you have to click on the items to make the movement direction the same and partly because some contstraints may resolve in a conflicting manner (often from overconstraining) causing one or more of the constraints to behave "erratic".

Piekaro

@RSW thank you for your message

the problem is, that now I even can not save anything more. It looks like there can be X Constraints and nothing more can be saved.
After "save" I have got a lot of RigidSets with only one surface, or even none of new Distances which i wanted to save. I have also a feeling that BIM_SUBSTRACT does not make it easier..

Piekaro

I used "Parametrize" command, to see how schould I use Constraints. Simple block. Only a few Parameters.
I did not change anything, just saved the file.
I opened it again - few parameters did not work.

I am totally confused - am I doing sth wrong or is it sth with Bricscad?
Can you please suggest me some good tutorials/articles with 3D parametric blocks? I found only 2-3 on youtube, but it does not explain a lot of problems.

RSW

I noticed that you have some "duplicate" rigid sets, i.e. a rigid set of two faces that are also included in a rigid set of 3 faces. The former one could be deleted without issues. Also it would be prudent to remove all single face rigid sets to make things more manageable.

Another thing is that you have some rigid sets that are referring to the same objects and some fixes to faces that belong to more than one rigid set in different combinations, so depending on what is changing it could force other objects to move/flip in an unintended way depending on which face/edge etc. is the driving component or one rigid set could end up blocking another one from behaving properly (i.e. as intended).

Auto-parametrizing is as far as I am concerned just for creating a starting point and should be optimized afterwards, i.e. remove any and all parameters/constraints you don't really need for the object and check the remaining ones for possible conflicts. Only you know what the intent is, auto-parametrize is just doing a best guess and may end up with combinations you don't want at all.

So despite of objects supposedly being underconstrained I prefer to use the bare minimum of constraints etc. where feasible to keep it as simple as possible and reduce the chance of conflicts/problems. To some extent this is a matter of trial and error in the beginning.

My guess, for now, is that the whole combination of rigid sets and fixes in your model has some conflicting combinations that are causing some (or all) of your issues. You may want to start over again and add fixes/constraints one at a time after the most basic ones and then test if it behaves properly. Once you get unwanted behaviour with a new rigid set you know where a conflicting set might be and then you could try creating a different rigid set that may work.

The more constraints/fixes/parameters you have the greater the chance that something is going to act up and create issues. It is the same with Solidworks etc.

Did you check the BricsCAD blog? Unfortunately most BricsCAD video's are too short on details to really learn how to use the tools. You may want to look for e.g. Solidworks tutorials about using constraints, there should be more for that software, it may be of use because the use of constraints in SolidWorks is very similar to BricsCAD and may give you some ideas about how to set up constraints in BricsCAD.

A lot of CAD software has (sometimes woefully) inadequate documentation that lets you keep searching all over the place and mention things in sections where you wouldn't expect or think of looking there or the information is so brief/generic that it is of no practical use.

Piekaro

@RSW thank you for your message,

I know that if it is about the number of constraints, it's follow the rule "less is more".
I am trying to create the blocks with some logic, I am thinking about the conflicts which can happen.
What you saw in this block is an error which Bricscad makes during the saving process. (RigidSet with only one surface, or with different surfaces). I had also a few distances, which are completely not saved... - and that is my problem.
When I see some highlighted constraints in mechanical browser, I know that it is an error in my logic. But when the software is loosing a constraints during the file saving, I don't know where is a mistake.

RSW

@Piekaro then I suggest you file a service request with the file(s) causing errors. I can imagine contrainst losing one or more faces after a solid editing operation (e.g. Join, subtract etc.) but not with just saving a file. That sounds much more like a bug somewhere in BricsCAD though in theory there might be some conflict resolving going on in the background but I would expect that to happen upon opening a file and not upon saving a file.

Piekaro

@RSW I followed your suggestion, and I made the same block once again, but with new file, new Bodies elements. All new, but I used exactly the same constraints, in the same way. I saved the file, opened it again - all work perfectly fine...

Tkank you for your answers - I guess I have somehow damaged files