Equation to fix/unfix the posi

skan · 发表于 2022-7-9 02:50:08

Hello

I need to disable or enable the dragging of a body depending on a certain condition, such as the position of another body or the value of an equation.

How can I get it?, Maybe linking some value to an equation?, How?

I've though that one way to achieve it would be using distance mates, something like:

minimum distance = 0
maximum distance = iff(condition=true, 100, 0)

That would allow to move the piece from 0 to 100 if the condition is true.

But it doesn't allow me to introduce equations there.

shift1313 · 发表于 2022-7-9 03:00:11

skan, can you give me a little more info about the assembly or conditions. My initial thought would be to use the $FIXED parameter in an equation in a design table. But the manual drag part is what im not sure how to work around. Inside excel in a design table you can fix/free the parts and the equation functionality in excel will be easier to implement this.

skan · 发表于 2022-7-9 03:06:19

Hello

I wasn´t speaking about any specific assembly, but I can give you an example:

Imagine I'm designing a lock with a key.
I want to be able to move the key in and out the hole.
It's easy to assign mates in order to restrict the position of key.

But once the key it's completely inserted and I rotate the cylinder lock (I start to open it) I need the key not to be extracted till the cylinder is rotated 360 degress.

The key will be allowed to move from distance 0cm (inner) to 10cm if the cylinder is at 0º (or 360º), but the distance will be fixed to 0cm otherwise.

How can I do it?

shift1313 · 发表于 2022-7-9 03:15:55

Well for instance such as that I have always run a motion study. This allows you to apply a Cam "mate" which takes into account the physical limitation. In your example the tumblers and grooves retaining the key. Ill have to give this a little thought. My first thought is that there is not a combination of mates that allow this motion but i wont give up that easy:)

skan · 发表于 2022-7-9 03:17:10

It would be doable if one could add vba code to the mates

skan · 发表于 2022-7-9 03:23:33

Another example would be a puzzle with sliding pieces or a Rubik puzzle, where each piece can move depending on the others

shift1313 · 发表于 2022-7-9 03:35:35

if you turn on physical dynamics and move your parts with the "move" command it will account for physical interference, but its a real drag on the system. The only thing i am coming up with is a path mate. If you have a point on your key(in that case) and you create a composite curve path the key can go in straight then rotate only following that path.

I dont know of a way to control mates with VBA, only fix/float and suppressing components. It still wouldnt allow the free drag which it sounds like thats what you are after...

skan · 发表于 2022-7-9 03:41:55

OK, thanks,
I'll it.

skan · 发表于 2022-7-9 03:45:30

The difficulty in my example, I FORGOT TO TELL IT, is that there are two restrictions:
1) The cylinder could only be moved if the key is completly inserted.
2) The key could only be inserted or extracted if the cylinder is at 0º.

Therefore, rotation (cylinder+key) and insertion (key) are mutually exclusive.

skan · 发表于 2022-7-9 03:50:15

Hi

I've being thinking again and youur suggestion is enough for my lock+key example, I'd use a curved path. Depending on the model I could even need several paths and linked points.

Other problems more difficult, such as the Rubik cube, may require a motion study

[综合讨论] Equation to fix/unfix the posi

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