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How can I mate hand-wrist-forearm so hand will also rotate as the wrist rotates?

Question asked by Brielle Lee on Jan 19, 2017
Latest reply on Jan 25, 2017 by Brielle Lee

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Hello everyone.

I'm trying to make a forearm model which I can use for other purpose.

I need this forearm's hand to do pitch and yaw as well as the wrist/forearm rotation.

For the parts, so far, I used couple coincident and concentric mates to hold the pieces together.

The problem was that if I try to mate the hand and wrist(blue part) together by mating planes.. it won't do either pitch or yaw.

As of now, since those two are not mated, if I rotate the wrist to replicate forearm supination/pronation, hand stays still and won't follow as the wrist rotates.

What mate can I use for this??

Also, I had trouble making an animation, and I wasn't sure if it was due to very flexible wrist joint so that's why I'm trying to assemble everything again.

Even though I had an angle limit mate for the device which was assembled on the forearm, when I tried to make the animation, the hand ignored that limit and bent as much as this hand can go. Animation wouldn't show smooth transition...

I can't show this device here, so it could be hard to understand what's going on.. but does anybody see what the problem is here?

Thanks,

Brielle

Brielle Lee Jan 25, 2017 1:12 PM

Correct Answer

Okay- I was able to find the solution by applying the perpendicular method Kristian recommended to here and there. Not of the blue part, but of the dome in front of the blue part, I made perpendicular mate and the problem was fixed. Now the palm and wrist move along together. So, it looks like I needed to make the perpendicular on the spherical joint.

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Frank Ruepp

Jan 20, 2017 1:40 AM

Hi Brielle,

the reason why your forearm does not behave as desired is because all mates are solved simultaneously and there is no solve hierarchy. Means all mates are equal and can move at the same time.

If I got you right you want to create an animation where i.e. the hand rotates together with the forearm but at a later stage moves separately in relation to the forearm.

A solution to this problem could be the "Mate Controller". With the mate controller you can control which mate should be moved and which one should not. In order to use "Mate Controller" you will have to set up limit mates like limit angle mates. After you have "imported" the limit mates you should be able to control individual mates, save specific points as positions and create an animation between saved positions.

Hope this helps

Kind regards

Frank

SOLIDWORKS Product Definition Team

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Brielle Lee @ Frank Ruepp on Jan 21, 2017 6:22 AM

Thanks! I don't have many limit mates, so I wasn't able to use mate controller yet, but I saw some youtube tutorials and it definitely looks useful. Later on, I can use this for animation/video. I have sw2015, and I wonder if mate controller is new feature for 2016 though. As of now, with Kristian's answer, I got the hand that follows the wrist with both pitch and yaw. Awesome!

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Brielle Lee @ Frank Ruepp on Jan 23, 2017 10:19 AM

Kristian's answer didn't solve the problem completely.. and my SW2015 doesn't have mate controller.. Do you have other recommendation?

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Kristian Strømstad Jan 20, 2017 6:30 AM

Try a perpendicular mate between the two planes I've drawn. The red one is in the wrist part and the green one in the hand.

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Brielle Lee @ Kristian Strømstad on Jan 21, 2017 6:22 AM

OMG, Genius! I thought it was not going to work because I tried coincident and parallel mates before, but I guess this is when I use perpendicular mate!!!! Thanks!

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Brielle Lee @ Kristian Strømstad on Jan 22, 2017 6:07 AM

Hey, Kristian (and others)

I thought it worked.. but actually this has some problem.

This works for about 90 degrees, but when I completely rotate the wrist part 180 degrees, then hand rotates 360 degrees, and goes back to above position. Hand won't flip upside down.............

What else can I do?

Best,

Brielle

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Brielle Lee @ Brielle Lee on Jan 25, 2017 1:12 PM

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7 Replies

Frank Ruepp Jan 20, 2017 1:40 AM
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Correct Answer
Hi Brielle,

the reason why your forearm does not behave as desired is because all mates are solved simultaneously and there is no solve hierarchy. Means all mates are equal and can move at the same time.
If I got you right you want to create an animation where i.e. the hand rotates together with the forearm but at a later stage moves separately in relation to the forearm.
A solution to this problem could be the "Mate Controller". With the mate controller you can control which mate should be moved and which one should not. In order to use "Mate Controller" you will have to set up limit mates like limit angle mates. After you have "imported" the limit mates you should be able to control individual mates, save specific points as positions and create an animation between saved positions.

Hope this helps
Kind regards
Frank
SOLIDWORKS Product Definition Team
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- Brielle Lee @ Frank Ruepp on Jan 21, 2017 6:22 AM
  Mark Correct
  Correct Answer
  Thanks! I don't have many limit mates, so I wasn't able to use mate controller yet, but I saw some youtube tutorials and it definitely looks useful. Later on, I can use this for animation/video. I have sw2015, and I wonder if mate controller is new feature for 2016 though. As of now, with Kristian's answer, I got the hand that follows the wrist with both pitch and yaw. Awesome!
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- Brielle Lee @ Frank Ruepp on Jan 23, 2017 10:19 AM
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  Correct Answer
  Kristian's answer didn't solve the problem completely.. and my SW2015 doesn't have mate controller.. Do you have other recommendation?
  Like • Show 0 Likes0
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Kristian Strømstad Jan 20, 2017 6:30 AM
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Correct Answer
Try a perpendicular mate between the two planes I've drawn. The red one is in the wrist part and the green one in the hand.
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- Brielle Lee @ Kristian Strømstad on Jan 21, 2017 6:22 AM
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  Correct Answer
  OMG, Genius! I thought it was not going to work because I tried coincident and parallel mates before, but I guess this is when I use perpendicular mate!!!! Thanks!
  Like • Show 1 Like1
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- Brielle Lee @ Kristian Strømstad on Jan 22, 2017 6:07 AM
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  Correct Answer
  Hey, Kristian (and others)
  
  I thought it worked.. but actually this has some problem.
  This works for about 90 degrees, but when I completely rotate the wrist part 180 degrees, then hand rotates 360 degrees, and goes back to above position. Hand won't flip upside down.............
  
  What else can I do?
  
  Best,
  Brielle
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  - Brielle Lee @ Brielle Lee on Jan 25, 2017 1:12 PM
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    Correct Answer
    Okay- I was able to find the solution by applying the perpendicular method Kristian recommended to here and there. Not of the blue part, but of the dome in front of the blue part, I made perpendicular mate and the problem was fixed. Now the palm and wrist move along together. So, it looks like I needed to make the perpendicular on the spherical joint.
    Like • Show 1 Like1
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How can I mate hand-wrist-forearm so hand will also rotate as the wrist rotates?

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