Subject:
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Re: What about a LEGO TECHNIC tutorial
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Newsgroups:
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lugnet.cad.mlcad
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Date:
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Tue, 7 Jun 2005 17:26:03 GMT
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Viewed:
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10332 times
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In lugnet.cad.mlcad, Dean Earley wrote:
> > One problem with technic designes is that axis of rotation are often not
> > parallel to the X,Y or Z planes. I use GROUPS to collect all parts related to a
> > rotation axis, so they are easy to work with. Then I rotate them so the
> > rotation axis is parallel to one of the X,Y, or Z axis'. From there, I rotate
> > the group the amount needed. I then have to reverse the original rotations to
> > get the group oriented back to the original rotation axis.
> >
> > It sure would be nice to be able to pick an axle or pin, and use that to
> > define a rotation axis. From there you could rotate the group clockwise or
> > counter clockwise.
>
> Select the part you want it to pivot around then select the rest.
> It will always pivot around the pivot point of the first item selected.
But, rotations are limited to parallel to the X,Y and Z planes, so I don't think
you are addressing what I'm talking about.
Imagin you had an axle that is at 45 degrees in the XY plane, and you have a
biped leg you want to rotate around the axle. Rotation about X, Y, or Z does
not help you here.
Is my understanding off base, or are you answering a question I didn't ask?
>
> > I spend a lot of time managing the rotation point.... being able to move it
> > small increments by the keyboard might help, but I've never studied MLCad enough
> > to know if it already exists.
>
> You can make it visible and draggable with the mouse.
I understand this, but the mouse is not always the greatest, and is not what I
was talking about. There are times where I'd like to be able to move the
rotation point around like any other part, thus allowing incremental fixed
length movements.
>
> > The width and height ratio stuff that LEGO is famous for is also a problem in
> > technic. Getting pins and axles precisely in the holes is a tough task,
> > especially if the axis of the pin is not parallel to X, Y, Z.
>
> Down 2 LDU :)
With rotations, the pin/axle holes are not necessarily on a nice grid boundary.
Dean, I can't tell from you answers if you were really trying to be helpful, or
just goofing around.
Kevin (is it April Fool's Day?)
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Message has 2 Replies:
 | | Re: What about a LEGO TECHNIC tutorial
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| (...) That's not true. It is true that doing rotations around arbitrary axes requires a lot more understanding of what's going on, but MLCAD allows you to define the full 3D vector around which the rotation happens, so you can rotate in any plane. (...) (19 years ago, 8-Jun-05, to lugnet.cad.mlcad)
| | | Re: What about a LEGO TECHNIC tutorial
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| (...) I think I forgot mentioning this yesterday, but that is excactly the point where it's practical to use submodels: Make a submodel with the axle and the biped leg. In the main model you turn the axle/submodel (45 degrees), and in the submodel (...) (19 years ago, 8-Jun-05, to lugnet.cad.mlcad)
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Message is in Reply To:
| | Re: What about a LEGO TECHNIC tutorial
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| (...) Select the part you want it to pivot around then select the rest. It will always pivot around the pivot point of the first item selected. (...) You can make it visible and draggable with the mouse. (...) Down 2 LDU :) (19 years ago, 6-Jun-05, to lugnet.cad.mlcad)
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