How difficult would it be to......?

kees_bijker

Imagine you have a certain part with a finger style profile. This part is sliding up and meets another part.

How difficult would it be to create a series of restrictions or mates, so that second part is resting in place, maybe in some holder, until the first part meets it in its upward motion and it then it moves with this first part in the upwards direction?

Secondly, imagine a third part which is also in the holder, which is also taken up by the first part but in an unstable position resting in the fingers and against the second part. Now as they move up, the position relative to each other changes and the third part drops into the second part while both still move upwards.

For me this is pure magic and it would represent difficulty level max. But for those here who actively use the simulation tools, and maybe feature script, is this even possible in onshape?

jan_bouwman

It depends on what you mean by ‘simulation’.

If you mean that Onshape will calculate all movements based on physical properties of the model, external forces like gravity, wind etc., detection of collisions, impacts, scattering and all of that, as far as I know, Onshape can not do that (yet). 

However, if you know (or guess) what the final movements are and how they look like, you can make an animation of the parts that move.

Of course, when you change the properties of the model afterwards, the animations will not adapt accordingly. You will have to do that manually.

For another thread I made a short video on what can be achieved with animation.

I will add the link here as well and I am happy to answer any questions you may have on the subject.

https://youtu.be/Llsd4rxHDV8?si=8MzuwKggTRR8ylBE

kees_bijker

jan_bouwman said:

It depends on what you mean by ‘simulation’.

If you mean that Onshape will calculate all movements based on physical properties of the model, external forces like gravity, wind etc., detection of collisions, impacts, scattering and all of that, as far as I know, Onshape can not do that (yet). 

However, if you know (or guess) what the final movements are and how they look like, you can make an animation of the parts that move.

Of course, when you change the properties of the model afterwards, the animations will not adapt accordingly. You will have to do that manually.

For another thread I made a short video on what can be achieved with animation.

I will add the link here as well and I am happy to answer any questions you may have on the subject.

https://youtu.be/Llsd4rxHDV8?si=8MzuwKggTRR8ylBE

Natuurlijk een wind molen voor een nederlands voorbeeld :-) Moest er wel om lachen als nederlandse emigrant.

Absolutely fantastic video and I think the hatch doors opening when the bag hits them, and they even move according to the shape of the bag is actually pretty close to what I was looking for tbh.

A real simulation was a bit far reached, since this is not in the package I use anyway, but this example where you animate the movements and other objects are responding to this movement is really nice.

How do you link the hatch door movements to the bag? Some tangent mate while the movement is limited to the closed position maybe?

Interesting to say the least.

jan_bouwman

Natuurlijk een wind molen voor een nederlands voorbeeld :-) Moest er wel om lachen als nederlandse emigrant.

Haha, volgende keer laat ik een paar klompen zien als voorbeeld van mijn vaardigheden met de Loft-tool.

(Haha, next time I will show you wooden shoes (Dutch clogs) as an example of my lofting skils  )

How do you link the hatch door movements to the bag? Some tangent mate while the movement is limited to the closed position maybe?

No… the hatches are driven by the timeline, not by the bag.
so no mates between hatch and bag. When I leave out the bag completely, the hatches move exactly the same.
The making of the timeline however was a tedious job: for every step I measured the angle of the hatch when it touches the bag and adapted the timeline accordingly.
This creates a ‘rippled’ timeline.
I hope this helps. This method requires a bit of ‘inside out’ thinking. Or is this a too Dutch expression 

Here is the series of timelines used for hoisting the bag.
I think you can find the timelines for the movement of the hatches. 

jan_bouwman

How do you link the hatch door movements to the bag? Some tangent mate while the movement is limited to the closed position maybe?

I’ve been thinking… in a way you are right! Although the actual shape of the bag is not used directly, the timeline does represent the shape of the bag in a certain way.
And the shape of the timeline is followed by a pointer, indeed with a tangent mate.
The vertical movement of the pointer is then transferred to the revolute mate of the hatch door by a Rack & Pinion relation.
The limits of the mates are not used. However, limits are implied by the amplitude of the timeline.
so…

Animation through a timeline makes the animation more generic: you do not have to mate the movable objects directly. And it has some other advantages.

Interesting…

kees_bijker

jan_bouwman said:

How do you link the hatch door movements to the bag? Some tangent mate while the movement is limited to the closed position maybe?

I’ve been thinking… in a way you are right! Although the actual shape of the bag is not used directly, the timeline does represent the shape of the bag in a certain way.
And the shape of the timeline is followed by a pointer, indeed with a tangent mate.
The vertical movement of the pointer is then transferred to the revolute mate of the hatch door by a Rack & Pinion relation.
The limits of the mates are not used. However, limits are implied by the amplitude of the timeline.
so…

Animation through a timeline makes the animation more generic: you do not have to mate the movable objects directly. And it has some other advantages.

Interesting…

That timeline is an interesting thing, not used that before, will look into it even if just for fun and out of interest.