topic Re: Limits to a constraint in Inventor Forum

Limits to a constraint

Anonymous — Sun, 03 Jul 2016 23:42:18 GMT

This is a YouTube video. To learn limit constraint I replicate it. Why is Bucket Handle coming inside the bucket.

Re: Limits to a constraint

Frank-Oosterwaal — Mon, 04 Jul 2016 06:32:19 GMT

Hi,

your mate 2 should be a flush constraint.

Change it and the hook will flip to the right position.

Re: Limits to a constraint

Anonymous — Mon, 04 Jul 2016 08:26:08 GMT

Thanks for your help. Could you tell me the reason please.

Re: Limits to a constraint

Frank-Oosterwaal — Mon, 04 Jul 2016 09:28:42 GMT

Hi,

Hmm let me see if I can explain this correctly:

The picture in the constraint dialog box really says it all.

The mate constraint will make the two selections face to face.

The flush constraint will make the two selections flush.

If you look at the pictures in the dialog box you can see that the two components will flip in orientation by changing it "mate" or "flush".

Better said, it will define the orientation of the two components to each other.

Therefore it will also define the orientation for your angle limit constraint.

In this case your "mate" constraint made the angle limit constraint behave the wrong way around.

By making the "mate" constraint "flush", the hook flipped in orientation to the bucket.

The angle constraint flipped with it and works now the right way around.

I hope I explained it well enough for you to understand...

Re: Limits to a constraint

Anonymous — Mon, 04 Jul 2016 12:56:59 GMT

From Edit Constraint dialog box image if object face is in opposite direction it is MATE, if object face is in same direction it is FLUSH.

It is difficult to identify these things if it is a origin plane alone. Is there any simple method to identify this?

Re: Limits to a constraint

JDMather — Mon, 04 Jul 2016 12:59:02 GMT

@Anonymous wrote:
It is difficult to identify this if it is origin plane alone.

Workplanes have a front side and a back side.

The front side is a lighter color.

The back side is a darker color.

Light side to light side, then Mate-Flush

Light side to dark side, then Mate

BTW - your "bucket" will hold 0.1 in ^3 (or 1.64 ml) of water.

Re: Limits to a constraint

Anonymous — Mon, 04 Jul 2016 13:20:20 GMT

Thanks for the explanation.

Re: Limits to a constraint

Anonymous — Mon, 04 Jul 2016 16:46:39 GMT

How to determine if you want place Bucket Handle upside then you have to FLUSH.

Is it by trial and error?

Re: Limits to a constraint

JDMather — Mon, 04 Jul 2016 17:20:39 GMT

You can tell by the color of the workplanes.

But that takes too much time (I seldom turn on the visibility of workplanes).

It is faster to just do it by trial and error.

I use several different CAD programs in a single day (often in a single hour), I don't even bother trying to remember or pre-determine the next step as it is so much faster to just do the opposite on these binary decisions if the first guess doesn't give me what I expect.

Something more complicated I will spend a bit more time, but if it is just one way or the other - just do it and observe the behavior. I suspect that would still be true even if I only used Inventor all day.

Re: Limits to a constraint

SBix26 — Mon, 04 Jul 2016 20:38:34 GMT

When choosing planes or faces for the Mate constraint (and angle constraint, too), Inventor places a temporary red arrow on the feature to indicate the normal direction. Unfortunately, these arrows are typically hidden by other geometry, but you can see them if you zoom way out, because they maintain their size on screen. These arrows really help to minimize guessing.

Sam B

Inventor Professional 2016 R3 SP2
Vault Basic 2016 SP1
Windows 7 Enterprise 64-bit, SP1

Re: Limits to a constraint

Anonymous — Tue, 05 Jul 2016 02:26:06 GMT

I use several different CAD programs in a single day (often in a single hour),

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Superman!