Dropping A Ball Through Roating Opening
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I'm having a problem figuring out how to get a ball to drop though an opening that is rotating. Attached is the model in SU v7.1 SP v3. The ball floats over the rotating platform and will not drop to the surface with the hole in it. I am wanting the ball to drop inside the hole and stay there while the hole is still spinning. The plate under the hole is supposed to keep the ball inside the hole. Any help is appreciated. Thanks
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I know there are attributes that you must select for your objects. I believe one is "static"? Right click on the group to pull up the settings window? I do not use SP yet, but I get this info from reading the related threads and SP faq found in the SketchyPhysics subforum here.
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Sketchy physics has a hard time with "voids". This means that if you want a "hole" in something to act as part of a whole you need to essentially build the "whole" by grouping together other shapes like boxes and convex hulls and leave some out for the hole. . Depending on your computer and its processing power you can build things out of pretty small strips which like with calculus, approximate reality...or at least a good facimile thereof. To get the idea I suggest starting with two rectangular boxes bound together by two squares leaving a void in the middle. Take those shapes and group them and wallah (sp). The good thing about rectangles is that they "scale" a little better. The attached model takes this two steps further by they grouping the groups together and then attaching a motor.
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Thanks MPTAK but that's not really what I'm going for. The problem seems to duplicate anytime I add a motor, hinge or servo joint. Without the joint it acts as it should but with the joint the ball will float over the hole..
@mptak said:
Sketchy physics has a hard time with "voids". This means that if you want a "hole" in something to act as part of a whole you need to essentially build the "whole" by grouping together other shapes like boxes and convex hulls and leave some out for the hole. . Depending on your computer and its processing power you can build things out of pretty small strips which like with calculus, approximate reality...or at least a good facimile thereof. To get the idea I suggest starting with two rectangular boxes bound together by two squares leaving a void in the middle. Take those shapes and group them and wallah (sp). The good thing about rectangles is that they "scale" a little better. The attached model takes this two steps further by they grouping the groups together and then attaching a motor.
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I played with this a little, I wonder if making the plate and the ball magnetic, so they are attracted to each other, will make the ball drop. I haven't worked the magnetic capabilities so I am not sure.
Interesting challenge though. -
TSPCO a magentic attraction wouldn't work as this is like a gumball dispenser mech in which a group of balls is introduced into a closed cylinder (not shown the model I posted) and the rotating wheel allows one ball to drop. The bottom plate has a hole (also not shown) so when the rotating wheel aligns with the plate the ball will drop though both holes thereby being dispensed out the bottom plate. I just now hadan idea that may serve as a work around. I'll post it in a few hours..It should work.
@tspco said:
I played with this a little, I wonder if making the plate and the ball magnetic, so they are attracted to each other, will make the ball drop. I haven't worked the magnetic capabilities so I am not sure.
Interesting challenge though. -
Here is a work around to the problem I was having. It's a simple fix and not very reliable. After a while it will either jam, or the push bars get out of alignment with the motor joint. I welcome any of you SP Pros to provide a better, reliable solution, if one is possible. Thanks in advance... -Joe
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Thanks to those who offered advice. The key was to make the push rods "ConvexHull" which basically shrink wraps the object. This model doesn't jam and most of the time only allows one ball to drop per rotation increment. After you start the animation press the "X" key to add as many balls as you want. Now I'll remove the center cone and try to create a spiral ball feed so that each of the slots only gets one ball at a time thereby elimanting a double ball drop.
FYI this is a rough draft of delivery mechanism for a gumball machine. This model was only to work out how to guide a ball to an opening and have it drop through.
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Cool contrivance, I ran the animation and it worked OK. But when I sped it up a little it would drop only one out of seven balls or so.
Thanks for sharing! -
The end result will be to turn the wheel 1/8 of a turn each time and dispense one ball so I didn't focus on speed. Try making the hole larger and it should dispense quicker. Which leads me to my next question... Anyone know how to make a motor turn just an 1/8 of 360 degrees with one press of a key? I could do this with a servo, but the servo would want to rotate back the other direction (to center) after the key is released. I haven't played with that part yet. One problem at a time I suppose!
@tspco said:
Cool contrivance, I ran the animation and it worked OK. But when I sped it up a little it would drop only one out of seven balls or so.
Thanks for sharing!
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