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Animation incosistencies, motion mates, keyframes.

Question asked by Vlad K on Apr 14, 2009
Latest reply on Apr 30, 2009 by Vlad K

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Hi to all,

I've been working on a trailer model for a few months now, and everything was going great

until i got to SW 2009 Motion Study.

My assembly is basically a mobile theme ride (trailer) which contains several folding and telescoping mechanical sub-assemblies (about 70 fully defined parts).

My problem specifically is the inconsistency of mate relations after i create and recalculate. It is very frustrating as after (by chance) rendering a successful animation i cannot really change small elements within, as i have to re-mate everything to achieve favorable results.

Now, i have done several successful animations in the past, but on a smaller scale, so there is some experience followed by a set of expectations for a given time frame.
But the current situation is disproving all of the confidence i gained from previous projects.

My workflow is disturbed drastically and everything relating to this animation is becoming more difficult day by day.
In turn i am also starting to have difficulties restraining my self from going nuts over such ill-logical happenings.

In the process, i have even invested in 8gb of ram and a stupidly fast Hard Drive with a x64 setup.
And all i get from my upgrades is a faster rendering time which is 100% worthless when the product is a tangled mess of parts.
By the way i am running an FX1700 video card.

ON a subtle note, i have noticed that a lot of the issues are consistent. For example, when i open the assembly file i know that after clicking the motion study tab i will have to change 4 mates for sure. The weird mate dimension numbers usually change to .704988 every time, when it should be 15.5 .

SO, just wondering if anyone has gone through this pain? and if there are any viable solutions to this craze.

No one else has this question

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John Ashton Apr 14, 2009 5:01 PM

Vlad K,
I feel your pain. I have countless hours invested in a relatively simple model and have experienced many problems similar to those you have expressed.

By the way I am still hoping for some forum help for my Motion Analysis problem 'Assembly Blows Up In Motion Analysis', in case anyone is listening.

I am by no means an expert but here are some hints that have helped with at least a few of the problems:

Eliminate redundant constraints - i.e. for fixed constraints use something such as plane-to-plane, plus line-to-plane, plus point-to-plane. I'm a little leary about using point to plane constraints but it seems to work most of the time. It is very easy to (mistakenly) constrain a unique degree of freedom two or three times in a single joint.

Eliminate distance constraints. Add material to one or more of your parts so that you can end up with only coincident or concentric mates. It sounds like that in your case you are only interested in an animation, so you should be able to just add bogus material as needed and then hide it so that it doesn't show up in the animation.

Prior to adding a new motion study: position the model in the viewing area and position any of the parts to the position that you want them to start out in, then select 'rebuild' or (cntrl + B), then I usually save it but I don't know why. Then select a new motion study and run your animation.

If at all possible, simplify, simplify, simplify. I find a huge portion of my really neat model stuff is totally unecessary.

Regards,
John Ashton

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Jeff Mowry Apr 14, 2009 5:51 PM

What John said is good practice, in my experience. I'll paste in something I've posted elsewhere that may be helpful, too. Some of the things you're experiencing might fit, some might not:

If the animation is more complex than a simple camera view moving around the assembly, you'll want a new assembly specifically made for animation.

Rule 1: Animator is buggy, and extremely resistant to edits without hosing your animation. Script (in text) out what you want to do, with the time intervals for each action, since you may need to reprogram your animation several times before it works properly.

Rule 2: Go through the built-in tutorials and all Help articles on Animator within SolidWorks. These are helpful, but not entirely accurate.

Rule 3: Reduce the complexity of your assembly as much as possible. This means everything that acts as a single mass should be a single part if possible. Cluster those things into a sub-assembly, then save the assembly as a part file. To further compact things, export that part file into parasolid (*.x_t) format, then reimport into SolidWorks. It's a dumb solid, but a quick one, probably made up of multiple bodies. SolidWorks can then treat this as a single part and drastically speed up animation.

Rule 4: If rendering with PhotoWorks, you must use native SolidWorks (not PhotoWorks) materials if you want anything to fade in or fade out, as the tutorials show. PhotoWorks materials will simply "snap" in and out--lame. But they look much more realistic. So unfortunately, you can't always get what you want, but if you try sometimes, you just might find you get what you need.

Rule 5: You can attempt to put different axes of movement on a part at the same time, but don't--it will only result in cranial hair loss. For complex motion, mate the moving part to a surface or curve (with a point or whatever) and move it along that face/curve incrementally for movement. Sometimes this doesn't work, and you'll need to patch in extra parts that are hidden until you need to move them. For instance, I did the animations at tommygate.com with the lift gates that fold down, sometimes unfold to make a larger lift surface, and then go to the ground. That required a ridiculous number of parts to pull off in Animator, since trying to string these sets of motion with the same sets of parts is impossible (don't know why, see Rule 1 above). So the gate folds down (1 part). Show already-down-gate (1 part), hide fold-down gate (can make this timing small, like 0.1 seconds). Unfold already-down-gate's extension gate (1 part). Show lower-to-ground gate (1 part), hide already-down-gate. Move lower-to-ground gate to ground, and go through the animation until it's time to reverse all those steps. You can see it's important to have simple parts in the assembly with all this duplication, or else you'll run out of RAM and crash, or have parts flying off the screen, or having your mates melt down, or whatever. Animator seems to have been made for a simple exploded view or a walk around your assembly--not for this sort of thing with multiple types of motion (rotation, translation, etc.) for the same part.

There are more rules, but that's enough to chew on for now. Good luck. Wear a helmet to prevent your hands from removing your hair.

Full disclosure: I've not yet attempted animations in v2009. There could be some new rules I've not yet seen, and perhaps even some bugs that have been worked out. But the things John mentioned regarding simplifying your assembly as much as possible (with mates and parts) is very important. I noticed that rebuilding my assembly will almost always force a part just a tad away from its starting position every time in my animation--causing necessary fixes--every time. Why does it do this? No idea--nothing I do changes the starting position of any parts in my assembly. This sort of thing is tough to take, but a full revision of your assembly--following a good script of what you've animated already--will help. In my experience Animator cannot handle an edit to the animation involving a new part or position of a part without a total reprogram of the animation. Since you'll be doing this often, write it all down and follow along.

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Vlad K Apr 16, 2009 12:03 AM

John, Jeff,

Thank you for your advice, all of your points make sense and i will try them tonight.

By the way, have you guys tried using the Width mate within the advanced mates menu? I have used it probably 10 times in my assembly, and have not had any problems relating to the associated parts.

What about fixing (f) components rather than using coincident mates?

VK

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David Blumenthal @ Vlad K on Apr 20, 2009 12:51 PM

Hi Vlad,

This is just a shot in the dark, but by any chance, do you have two mates with the same name? That's the only issue I know of in 2009 where mates could be assigned the wrong value in a motion study.

If you continue to have problems with that kind of issue, make sure to report this to your VAR.

Thanks,
-Dave

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Vlad K Apr 30, 2009 1:01 AM

Going along here,

A lot of the mate issues were fixed by creating new mates in Motion Study environment while deleting the original relations within the model.

Again, thanks to all for the advice.

Actions

5 Replies

John Ashton Apr 14, 2009 5:01 PM
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Correct Answer
Vlad K,
I feel your pain. I have countless hours invested in a relatively simple model and have experienced many problems similar to those you have expressed.

By the way I am still hoping for some forum help for my Motion Analysis problem 'Assembly Blows Up In Motion Analysis', in case anyone is listening.

I am by no means an expert but here are some hints that have helped with at least a few of the problems:

Eliminate redundant constraints - i.e. for fixed constraints use something such as plane-to-plane, plus line-to-plane, plus point-to-plane. I'm a little leary about using point to plane constraints but it seems to work most of the time. It is very easy to (mistakenly) constrain a unique degree of freedom two or three times in a single joint.

Eliminate distance constraints. Add material to one or more of your parts so that you can end up with only coincident or concentric mates. It sounds like that in your case you are only interested in an animation, so you should be able to just add bogus material as needed and then hide it so that it doesn't show up in the animation.

Prior to adding a new motion study: position the model in the viewing area and position any of the parts to the position that you want them to start out in, then select 'rebuild' or (cntrl + B), then I usually save it but I don't know why. Then select a new motion study and run your animation.

If at all possible, simplify, simplify, simplify. I find a huge portion of my really neat model stuff is totally unecessary.

Regards,
John Ashton
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Jeff Mowry Apr 14, 2009 5:51 PM
Mark Correct
Correct Answer
What John said is good practice, in my experience. I'll paste in something I've posted elsewhere that may be helpful, too. Some of the things you're experiencing might fit, some might not:

If the animation is more complex than a simple camera view moving around the assembly, you'll want a new assembly specifically made for animation.

Rule 1: Animator is buggy, and extremely resistant to edits without hosing your animation. Script (in text) out what you want to do, with the time intervals for each action, since you may need to reprogram your animation several times before it works properly.

Rule 2: Go through the built-in tutorials and all Help articles on Animator within SolidWorks. These are helpful, but not entirely accurate.

Rule 3: Reduce the complexity of your assembly as much as possible. This means everything that acts as a single mass should be a single part if possible. Cluster those things into a sub-assembly, then save the assembly as a part file. To further compact things, export that part file into parasolid (*.x_t) format, then reimport into SolidWorks. It's a dumb solid, but a quick one, probably made up of multiple bodies. SolidWorks can then treat this as a single part and drastically speed up animation.

Rule 4: If rendering with PhotoWorks, you must use native SolidWorks (not PhotoWorks) materials if you want anything to fade in or fade out, as the tutorials show. PhotoWorks materials will simply "snap" in and out--lame. But they look much more realistic. So unfortunately, you can't always get what you want, but if you try sometimes, you just might find you get what you need.

Rule 5: You can attempt to put different axes of movement on a part at the same time, but don't--it will only result in cranial hair loss. For complex motion, mate the moving part to a surface or curve (with a point or whatever) and move it along that face/curve incrementally for movement. Sometimes this doesn't work, and you'll need to patch in extra parts that are hidden until you need to move them. For instance, I did the animations at tommygate.com with the lift gates that fold down, sometimes unfold to make a larger lift surface, and then go to the ground. That required a ridiculous number of parts to pull off in Animator, since trying to string these sets of motion with the same sets of parts is impossible (don't know why, see Rule 1 above). So the gate folds down (1 part). Show already-down-gate (1 part), hide fold-down gate (can make this timing small, like 0.1 seconds). Unfold already-down-gate's extension gate (1 part). Show lower-to-ground gate (1 part), hide already-down-gate. Move lower-to-ground gate to ground, and go through the animation until it's time to reverse all those steps. You can see it's important to have simple parts in the assembly with all this duplication, or else you'll run out of RAM and crash, or have parts flying off the screen, or having your mates melt down, or whatever. Animator seems to have been made for a simple exploded view or a walk around your assembly--not for this sort of thing with multiple types of motion (rotation, translation, etc.) for the same part.

There are more rules, but that's enough to chew on for now. Good luck. Wear a helmet to prevent your hands from removing your hair.

Full disclosure: I've not yet attempted animations in v2009. There could be some new rules I've not yet seen, and perhaps even some bugs that have been worked out. But the things John mentioned regarding simplifying your assembly as much as possible (with mates and parts) is very important. I noticed that rebuilding my assembly will almost always force a part just a tad away from its starting position every time in my animation--causing necessary fixes--every time. Why does it do this? No idea--nothing I do changes the starting position of any parts in my assembly. This sort of thing is tough to take, but a full revision of your assembly--following a good script of what you've animated already--will help. In my experience Animator cannot handle an edit to the animation involving a new part or position of a part without a total reprogram of the animation. Since you'll be doing this often, write it all down and follow along.
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Vlad K Apr 16, 2009 12:03 AM
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John, Jeff,

Thank you for your advice, all of your points make sense and i will try them tonight.

By the way, have you guys tried using the Width mate within the advanced mates menu? I have used it probably 10 times in my assembly, and have not had any problems relating to the associated parts.

What about fixing (f) components rather than using coincident mates?

VK
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- David Blumenthal @ Vlad K on Apr 20, 2009 12:51 PM
  Mark Correct
  Correct Answer
  Hi Vlad,
  
  This is just a shot in the dark, but by any chance, do you have two mates with the same name? That's the only issue I know of in 2009 where mates could be assigned the wrong value in a motion study.
  
  If you continue to have problems with that kind of issue, make sure to report this to your VAR.
  
  Thanks,
  -Dave
  Like • Show 0 Likes0
  Actions
Vlad K Apr 30, 2009 1:01 AM
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Correct Answer
Going along here,

A lot of the mate issues were fixed by creating new mates in Motion Study environment while deleting the original relations within the model.

Again, thanks to all for the advice.
Like • Show 0 Likes0
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Animation incosistencies, motion mates, keyframes.

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