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Old 6th June 2008, 03:42 PM   #1
Crazzy INC
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Question object with 2 or more centres

Is AC3D able to make an object with 2 centres trying to draw complex machinery
like push rods and bushings
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Old 7th June 2008, 05:03 PM   #2
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Default Re: object with 2 or more centres

I don't think you can have two centers in one object, but you can combine more than one object into a group, if that's helpful.
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Old 8th June 2008, 07:28 PM   #3
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Default Re: object with 2 or more centres

i know i can make a group that has multi centres one per object
i'm trying to build a pivot point and or a liner motion out of a crankshaf
need to know if i can lock a plane

i'm working on a software fix if i can get my math right that is
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Old 9th June 2008, 09:46 AM   #4
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Default Re: object with 2 or more centres

Just curious, are you trying to generate a plane constraint for export reasons, or to assist in modeling?

Something else that might (or might not) be helpful, the "Move Toward" plug-in. It has source code, too: http://supercoldmilk.com/ac3dplug/movetoward.html

If you are only looking for the constraint for modeling (won't help if you're writing an exporter) this trick sometimes works: AC3D will constrain to the major axis if you hold down the control key. If you have a plane that's on an odd angle, one thing you can do is rotate the entire model so that the plane you want to constrain to is aligned to an axis, then move your object using the axis constraint with the control key, then rotate the whole thing back to it's original position. This trick works well for planar-mapping sloped objects, too.
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Old 9th June 2008, 10:23 PM   #5
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Default Re: object with 2 or more centres

i'm try to draw a simple crank and piston
that i can export as a x file
useing it in a darkbaick porgam as a prop
would like to just rotate the carank angle
and have the rest of mecanisum work as it would if real
ie the piston travels in a strait line without limb angle changes in the sofware
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Old 10th June 2008, 01:51 AM   #6
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Default Re: object with 2 or more centres

Nifty!

Won't that take more than two points though? For a full crankshaft with pistons attached--assuming the crank is driving the piston heads as well as the rods--wouldn't you really need a full kinematics setup?
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Old 12th June 2008, 11:27 PM   #7
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Default Re: object with 2 or more centres

i'm not trying to modle a moter per say
i'm trying to modke a vibrating feered
it uses excentric bearings to move a metal box up and forwoard
about 60 times per sec
it sets on bushing arms
basicly i would like to know if ac3D can constraine a limb (as Dark basic sees it)
to a given motion based on the input from the parent limb (or group)
so as the "crank" turns can i make the group(or limb) not turn with it but pivit to stay in a strait line motion

i'v done it with software math .....LOTS OF TRIG
slow thing down

like to know if ac3D can do it for me
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Old 17th June 2008, 05:54 PM   #8
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Default Re: object with 2 or more centres

Not that I know of.

In fact, I'm not sure of too many file formats that will export constraints that way... most will save skeletons, but obj\x\etc don't do constraints AFAIK. I believe Collada format will, but only with the physics extensions, and I don't think there's an exporter for that.

What format are other DarkBasic users using to do the same thing?
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Old 17th June 2008, 08:35 PM   #9
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Default Re: object with 2 or more centres

far as i know no one else its trying too do exactly what i'm trying

dose any cad program let you put constraints on any object

i'm trying to draw a drive chain now will see how much math it takes to
make look real

but would be nice if the object did it for me





i'v made the piston work with math
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Old 17th June 2008, 08:38 PM   #10
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Default Re: object with 2 or more centres

i'v made the piston work with math





looks some what convinsing
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