How do I reverse the direction of a Slider Mate?

john_smith077

Hello

How do I reverse the direction of a Slider Mate?

i.e. When I create a slider mate, when I tick Limits and enter a value for Z maximum, my part can now slide down the z axis. However it is sliding the wrong direction down the z axis and my two parts are now crashing into each other instead of sliding apart. Negative values for the maximum are not accepted. 

J

peter_hall

@viru Spot on, by using negative and/or positive numbers you can reverse the slide direction. You can also offset unless one of your values is 0. All you must remember is the maximum value always has to be bigger than the minimum value. My only confusion is which way is + and which way is - , I normaly have to trial it using the play button.

brucebartlett

I have not tested this, but my first thought is to change the direction of 1 of the mate connector's so the z (blue) axis is pointing the opposite direction. 

edit** not 1 of the mate connectors but both. Sorry for any confusion.

john_smith077

brucebartlett said:

I have not tested this, but my first thought is to change the direction of 1 of the mate connector's so the z (blue) axis is pointing the opposite direction. 

1. I couldn't work out how to do this
2. The Z blue axis on each part's surface always seem to point away from the solid that they are one....

EDIT: This is driving me *nuts*. Whatever the answer is it's not obvious!

brucebartlett

I just got a chance to test this, you have to find both the mate connectors associated to the slider mate and flip each of their z directions. see this gif.

viru

@john_smith077 , You have to put minimum value and maximum value correctly then only it will accept. For example: I required sliding motion from 0 to 100 inch range. In both value 0 is minimum value and 100 is maximum value. If we put 0 in maximum value limit then it would not accept it. Similarly for reverse direction it will slide in range of 0 to -100 inch. User has to put -100 in minimum value and 0 in maximum value limit. Kindly refer below video for more detail.

It will accept negative value also in maximum limit. For example:  sliding range of any part in between -100 inch and -20 inch. then you have to put minimum limit as -100 inch and maximum limit as -20 inch. It will accept. I hope this will be helpful to you.

brucebartlett

Thanks @viru that makes sense, great solution . My flipping make connector solution was not really ideal and my gif missed the final step to get the keyway back on the bottom. However it is important to understand how to reorient mate connectors, can be very handy to get a solution.

john_smith077

OK thanks Bruce and Viru both.

Yes that works. I ended up doing a combination of both solutions. I do think that it is counter-intuitive how this works. Surely there really ought to be a way of changing the primary directly of the slide other than:
a) flipping BOTH parts
b) using negative numbers

I'll put something into the suggestions thread. 

Anyhow many thanks!


PS How do you create those animated GIFs? (I've seen them used in other CAD forums...)

coleman

I've had difficulties with mate limits.  For some reason I just can't seem to figure them out.  Flipping the mates reorients the parts.  Sometimes the negative limit doesn't work or adjust ajacent parts incorrectly.  Also the revolute mate limit does not accept negative values.  

When I am setting mate limits it seems like I use trial and error for about 10 minutes and then abandon the damn mate limit.  

daniel_chow

Viru and Bruce, thanks! Your suggestions worked! Viru - I didn't know that was possible.

peter_hall

@viru Spot on, by using negative and/or positive numbers you can reverse the slide direction. You can also offset unless one of your values is 0. All you must remember is the maximum value always has to be bigger than the minimum value. My only confusion is which way is + and which way is - , I normaly have to trial it using the play button.

john_smith077

Personally I think Onshape isn't as helpful/intuitive as is should be on this. For example if you make the Maximum smaller than the Minimum e.g. by putting  a negative number into the maximum I suggest that is should ask you something helpful like "Would you like to reverse the direction of the slide?" Or it could put the negative number into the Minimum field for you....

jakeramsley

I have gotten into the behavior or moving my components into their non-0 mate limit to determine which direction the mate is in.  As you can see in @viru's post when the play button is pressed that the values of the mate are displayed on the screen.  This indicates to me whether I am setting a minimum or a maximum (even though in my mind it is a maximum).

The problem with 0 is that there is no indication which way is positive and which way is negative.

daniel_chow

peter_hall said:

@viru Spot on, by using negative and/or positive numbers you can reverse the slide direction. You can also offset unless one of your values is 0. All you must remember is the maximum value always has to be bigger than the minimum value. My only confusion is which way is + and which way is - , I normaly have to trial it using the play button.

Wish I can upvote Viru's post twice, I didn't realize you could enter a negative number and reverse the direction! Thats even faster than editing the mate connector. Less click that is... now I have two ways of reversing the direction. I tend to like Viru's method of using neg values rather than editing the mate connector b/c as John mentioned, sometimes editing the mate connectors flips the parts unexpectedly. Which is not a big deal, but then you have to flip them back. 

John, I'm not sure how much more intuitive you want it to be. It didn't take me long to figure out mate connectors and direction, and I'm a beginner. 

3dcad

daniel_chow said:

John, I'm not sure how much more intuitive you want it to be. It didn't take me long to figure out mate connectors and direction, and I'm a beginner. 

I agree, when I first started to play with limits it only took few minutes to figure out how to set up different directions using negative parameters.
I like to keep things simple, easy to memorize.. if you compare this to financial software, it is much better to simply put minus to expenses than put all values positive and tag them with credit/debet and create calculation rules that convert things - sometimes less automation is more productivity.

john_smith077

daniel_chow said:

John, I'm not sure how much more intuitive you want it to be. 

What are you talking about? 

If the functionality that required is to reverse the direction, and if we are genuinely talking about tying to make this application intuitive to new users, why not have a button that says "Reverse direction" ?

Forcing the user to guess both: 
a) that you need to put a negative number
b) that the negative number is not allowed to put put into the Maximum field (because you will get a different error if you try that)...

Yes, it's fine once you know it. Yes, it's fine if you happen to stumble across it. And now that we cognoscenti know how it works, we probably don't care to have it changed...

However on no planet is this genuinely "intuitive" - and certainly not as intuitive as it could be!

alex_ryan

I WAS able to make this work using flippage of the axes.  Took some fiddling but makes sense now.