[Help] Servo won't move, tell me why? [File included]
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Hi,
I've been stuck for 2 days trying to solve an issue and finally broke down to write a message here.
My problem is I'm trying to make a servo motor I modeled act like a servo. Using Sketchy Physics 3.2 on windows OR mac (I tried both), I've attempted to get the top part of my servo to spin. I've understand how to use joints to move objects as I've done so in other tests successfully.
Just to demonstrate.
1.) You create the servo joint (I scale it down to appropriate size) and set it's axis to how I want it to spin.
2.) I attach this to the object I want to move (in this case the servo head).
3.) I group the servo joint and the servo head into a group.
4.) Using the joint connector button, I click the joint inside the group hold control and click the servo base (part of the servo that does not rotate) as the reference.What it should do is when I click run a slider bar should appear that lets me rotate the servo arm. What happens for me is nothing! I move the slider bar and nothing seems to happen.
I've tried...
- Adding a floor (didn't work)
- Using Mac OS X (Lion), didn't work (some midi missing error did occur but read up about it and it should work anyways)
- Using Windows 7
- Creating new files (without using my model and new shapes) (works!)
- Create new file (with my model) (doesn't work??)
I went through a lot of trouble ( a good 6 hours) to model the servo exactly to the 1/10th of a millimeter accuracy. This is why I want to use the existing model. In case you are curious it's modeling a JRServo DSR581 with 127ounces per inch of torque.
The file with the problem is linked here on my server
http://www.itechware.com/downloads/servowontspin.skp
Any help is much appreciated, thank you! I can donate $5 by PayPal for help.
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Looks like some sort of scale issue. Scale your model up by around 10x than it runs fine. Good luck.
Ogan -
Actually I did some more tests and it appears the density value has something to do with it, when I changed the density to 10 for the objects it started working correctly (I had to add a floor since the objects instantly started to drop). Apparently the smaller the object is there more density it needs to work. I'm not sure why... anyone have any idea why this is the case?
What does density really do?
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What do you mean?
Density just sits there. Things that are denser just sit there harder. Density is weight per unit volume. -
First, thanks for taking the time to respond mitcorb and oganocali.
I must have implied that I didn't know what density 'really' was. As for density being weight per unit volume I understand.
In the context I was speaking, I was explaining that density is a value you can give in sketchy physics to any 'group'. Therefore density is how the program interprets it to be. I was asking how it was 'supposed' to act for the program and what it's intended purpose was (like to be given an example to where it's used correctly).
What I'm trying to argue is that the density should not interfere with the joints trying to rotate an object or not. It appears for small objects a high density number is required before rotation or ANY kind of joint movement for that matter can happen. I'm saying this is a bug.
http://code.google.com/p/sketchyphysics/issues/detail?id=29
Proof of the bug is listed here, that is where I found my answer. If you find it to be a bug also please star the issue.
Thank you.
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I read somewhere that you shouldn't scale the joints, or they might not work. You can hide them on their own layer (provided).
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My apologies for not being much help. I think density may have been intended for buoyancy. It seems I viewed at least one example demonstration of an assembly involving water.
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make them a little bigger
I do not need to be paid is still a hobbygreetings Frans
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I think I recognize that servo....Who else is drawing the links between Arduino and Sketchy Physics?
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Can you post files in V6 ? (Save as )
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