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In lugnet.cad.mlcad, Jeremy Vandivere wrote:
> Hi everyone,
> I just started getting interested in lego modeling in MLcad, and I am
> really enjoying it. I am having a little trouble with it though..maybe
> you can help me out...
>
> I have placed a part (plate 1x2) into the work area, and I need to
> rotate it along the X axis. in the 'enter position and rotation' dialog,
> it says the angle is already 90 degrees. this is referring the the 90
> degrees I had to rotate it to get it pointed long ways instead of
> sideways. (can you tell I'm new?)
>
> Basically a breakdown/tutorial of the enter position & rotation dialog
> would be greatly helpful. Does anyone know where I might find such a thing?
>
> Thanks for your help!
> --Jeremy
>
> PS: playing with this program has prompted me to buy my first real lego
> set in years. Anyone know when spider-man parts will be added to the
> parts list? :)
What you're trying to do is define a rotation vector, which can also be
explained as a "custom-oriented axis". Its origin is always 0,0,0 and it will
extend in the direction set by the XYZ coordinates.
This way of working is very powerful, meaning it can take very few actions to
achieve complex rotations. But it can get tricky to figure out all the maths
(rotation matrices are even more extreme in both counts).
One thing that you can try is unchecking the "Absolute" (values) checkbox at the
bottom of the dialog. That will enable you to do it step by step.
For instance, in your case it seems like you have the following XYZ value to
define the rotation vector (0,1,0) and 90 as the rotation angle.
So that is a 90-degree rotation across a custom axis that passes 0,0,0 and 0,1,0
(yep, that "custom axis" is in the same palce that the Y axis).
Now, uncheck "absolute". set the rotation vector values to 1,0,0 and type in the
angle that you want for the roof slopes rotation. That will rotate them in the x
axis.
Note: I don't remember and I can't look into this right now, but the whole 0,0,0
origin might mean that you have to place your parts in the world origin (0,0,0)
to perform the rotation and then move them backl to where they belong.
I hope this helps. In the book "Lego Software Powertools", we included an
illustrated description of this and the rotation matrices process. Also, the
POVray help file includes a very short but good description of rotation
matrices.
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In lugnet.cad.mlcad, Jeremy Vandivere wrote:
> Thanks for the prompt reply. :)
>
> I am aware of the rotate buttons, and have been using them allot. I even
> reset the button for the axis I'm working with to step 1 instead of 15,
> to try and get it lined up. It's still not working. :)
>
> To give you an idea....I'll show you the model I'm building...
>
> http://library.brickshelf.com/cgi-bin/gallery.cgi?f=1473
>
> I built this model at a friends house a couple of years ago. I noticed
> it at brickshelf, and decided I could try to model it in MLCad.
> My first mistake was starting off in the fine grid mode. after getting
> 80% built, and having to exactly position each piece..I realized I could
> highlight the whole thing and snap to the large grid. Viola...a little
> extra lining things up, and it was all fine....
>
> Then I got to the roof sections. I figured out that an angle of '53'
> will line the red pieces up with the black roof struts, (in step 16 and
> 17) however trying to get the black pieces lined up with that has been
> seemingly impossible. I realize now I probably would have been better
> off to assemble the roof pieces horizontally then rotate the whole thing
> to fit the struts...but I didn't do it like that.
Well I'd recommend doing it that way, as it is MUCH easier. The problem moving
pieces at strange angles is that the default movement is in x, y or z direction
- not in the direction that they are rotated.
Remember also that you don't have to add parts in the order you want them to
appear in the file - you can drag and drop them in the parts list window to
change the order after you're finished placing them.
Also, submodels give you yet another way of doing tricky things like this -
check out the Multipart menu.
> so now I'm trying to figure out how to read the DAT file. I want to know
> what each of those segments are in the position and rotation sections. I
> think if I can learn that, then the 'enter position and rotation dialog'
> will be old hat.
Well yes and no - the specification is here
http://www.ldraw.org/modules.php?op=modload&name=News&file=article&sid=45 but
editing the file manually is not something that is particularly easy - I have
done it on occasion (mostly when authoring parts) but it's rarely the easiest
way to do things.
ROSCO
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In lugnet.cad.mlcad, Jeremy Vandivere wrote:
> Thanks for the prompt reply. :)
>
> I am aware of the rotate buttons, and have been using them allot. I even
> reset the button for the axis I'm working with to step 1 instead of 15,
> to try and get it lined up. It's still not working. :)
I'm not sure what you're saying here, but I'll take a stab at it anyways. If
you highlight a piece that you placed earlier in the list, before you started
messing with angles, and then add your new piece there, it'll take it's
rotational geometry and positioning grid from that piece. You can then
click/drag that part entry in the text list to the step where you want it added,
and it will keep its correct rotational geometry and positioning grid, and it
will then provide the default numbers for the next part you place after it.
> To give you an idea....I'll show you the model I'm building...
>
> http://library.brickshelf.com/cgi-bin/gallery.cgi?f=1473
>
> I built this model at a friends house a couple of years ago. I noticed
> it at brickshelf, and decided I could try to model it in MLCad.
> My first mistake was starting off in the fine grid mode.
That really depends on how you'll be building. I've found that when you start
rotating bricks in odd directions for SNOT construction, later parts never line
up correctly unless you're using the fine-tune grid. 300% magnification quickly
becomes your friend.
> after getting 80% built, and having to exactly position each piece..I
> realized I could highlight the whole thing and snap to the large grid.
> Viola...a little extra lining things up, and it was all fine....
For something like that, you'll probably be better off placing each brick on the
screen in the order shown in the instructions, but leave stuff like the ladder
off to the side until you've moved past it a few steps and then go back and
reposition it. Every piece you place takes its starting point geometry from the
previous piece, so if you flip a part 22.5 degrees in one direction, flip it
22.5 degrees in an perpendicular direction, slide it one stud in each axis, and
then straighten it back up, it won't match the previous parts exactly, and
neither will any piece that you add directly behind it. In the Position field
in the parts list, each whole unit represents one LEGO Unit (the side faces on a
1x1 brick are 5LU wide and 6LU tall, and studs are about 1LU tall), and if you
start messing around with non-90 degree angles, you'll end up with parts that
aren't in X.000/Y.000/Z.000 coordinates. Since the fine-tune grid only moves it
1LU in any given direction, you'll never get rid of a fractional position unless
you can exactly retrace the adjustments that got you there, or you go in and
manually tweak the numbers.
> Then I got to the roof sections. I figured out that an angle of '53'
> will line the red pieces up with the black roof struts, (in step 16 and
> 17) however trying to get the black pieces lined up with that has been
> seemingly impossible. I realize now I probably would have been better
> off to assemble the roof pieces horizontally then rotate the whole thing
> to fit the struts...but I didn't do it like that.
Yeah, I figured that out when trying to assemble the legs for my recent Kumo
assassination spider. I had to delete all of the pieces I'd added after
starting them because they wouldn't ever line up with the original grid. What I
ended up doing instead was building the rest of the model first, and then
assembling the legs flat, pivoting entire sections into place, and then once the
legs were all built correctly, positioning them on the model (though the parts
are split up so that each leg only gets one piece per step).
> Also...anyone know if that ladder piece found in step 10 exists?
Other Parts/B/Bar 7 x 3 with Double Clips.
> so now I'm trying to figure out how to read the DAT file. I want to know
> what each of those segments are in the position and rotation sections. I
> think if I can learn that, then the 'enter position and rotation dialog'
> will be old hat.
Now that I can't help you with. I've figured out how to tweak the angle on a
single piece with a single axis of non-perpendicular rotation by editing the
actual LDR file, but it doesn't help for multi-part adjustments or for parts
that are tipped in two or three axes. And it doesn't guarantee that you'll be
able to place it correctly afterwards.
> Again, thanks to you all for your quick responses. Looks like this is
> the place to go to get help :)
To be fair, I just downloaded my copy last week, so I'm working my way through
some of the same problems myself (I hadn't even found the manual
movement/rotation feature yet).
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Thanks for the prompt reply. :)
I am aware of the rotate buttons, and have been using them allot. I even
reset the button for the axis I'm working with to step 1 instead of 15,
to try and get it lined up. It's still not working. :)
To give you an idea....I'll show you the model I'm building...
http://library.brickshelf.com/cgi-bin/gallery.cgi?f=1473
I built this model at a friends house a couple of years ago. I noticed
it at brickshelf, and decided I could try to model it in MLCad.
My first mistake was starting off in the fine grid mode. after getting
80% built, and having to exactly position each piece..I realized I could
highlight the whole thing and snap to the large grid. Viola...a little
extra lining things up, and it was all fine....
Then I got to the roof sections. I figured out that an angle of '53'
will line the red pieces up with the black roof struts, (in step 16 and
17) however trying to get the black pieces lined up with that has been
seemingly impossible. I realize now I probably would have been better
off to assemble the roof pieces horizontally then rotate the whole thing
to fit the struts...but I didn't do it like that.
Also...anyone know if that ladder piece found in step 10 exists?
so now I'm trying to figure out how to read the DAT file. I want to know
what each of those segments are in the position and rotation sections. I
think if I can learn that, then the 'enter position and rotation dialog'
will be old hat.
Again, thanks to you all for your quick responses. Looks like this is
the place to go to get help :)
--Jeremy
Purple Dave wrote:
> In lugnet.cad.mlcad, Jeremy Vandivere wrote:
>
> > I have placed a part (plate 1x2) into the work area, and I need to
> > rotate it along the X axis. in the 'enter position and rotation' dialog,
> > it says the angle is already 90 degrees. this is referring the the 90
> > degrees I had to rotate it to get it pointed long ways instead of
> > sideways. (can you tell I'm new?)
>
>
> If you're using MLcad, there should be a toolbar with six circular arrow buttons
> in it. Those arrow bottons will rotate the part along all three axes. The
> arrows are modeled according to the top-view (default lower left frame), where
> the left pair of arrows will roll it along a horizontal axis, the right pair
> will rotate it on a vertical axis, and the middle pair will spin it flat on the
> screen. Just make sure you have the right part selected before you start
> hitting the rotate buttons.
>
>
> > PS: playing with this program has prompted me to buy my first real lego
> > set in years. Anyone know when spider-man parts will be added to the
> > parts list? :)
>
>
> It's all a matter of when someone wants it bad enough to program it in. There's
> a noticable shortage of painted parts compared to what has been officially
> released, even though the shapes are already there, and minifigs are no
> exception. I get the idea that most of the part designers are interested in
> building new shapes instead of adding various skins to them.
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At 01:20 AM 7/28/2004 +0000, Purple Dave wrote:
> In lugnet.cad.mlcad, Jeremy Vandivere wrote:
> > I have placed a part (plate 1x2) into the work area, and I need to
> > rotate it along the X axis. in the 'enter position and rotation' dialog,
> > it says the angle is already 90 degrees. this is referring the the 90
> > degrees I had to rotate it to get it pointed long ways instead of
> > sideways. (can you tell I'm new?)
>
> If you're using MLcad, there should be a toolbar with six circular arrow
> buttons
> in it. Those arrow bottons will rotate the part along all three axes. The
> arrows are modeled according to the top-view (default lower left frame), where
> the left pair of arrows will roll it along a horizontal axis, the right pair
> will rotate it on a vertical axis, and the middle pair will spin it flat
> on the
> screen. Just make sure you have the right part selected before you start
> hitting the rotate buttons.
There are also keyboard shortcuts for those operations.
Rotate around Y axis: 'A' and Ctrl+right or left arrows
Rotate around X axis: Ctrl+up or down arrrows
Rotate aournd Z azis: Ctrl+'home' or 'end'
--Ryan
http://users.ifriendly.com/fourfarrs1
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