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What Units (not Measurement!)


Mike Twining

What global units do you prefer?  

17 members have voted

  1. 1. What global units do you prefer?

    • X, Y, Z
      15
    • Length, Width, Height
      2
    • Pan, Tilt, Roll
      0


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I've spent more time trying to figure out if x=length or if roll=z or if height=tilt. I can't take it anymore. I believe there should be ONE standard coordinate refrence for all of IronCAD. Currently we have

 

X,Y,Z

World Coordinates

Analysis Tool

 

L,W,H

Shape and sizebox

Animation moves

 

Tilt,Pan,Roll

Animation Rotations

 

...this is crazy. We need 2 of these GONE!

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I totally agree. No need for 3 sets of symbols to describe the same vectors. XYZ is the least ambiguous - most everyone has attended a geometry class in which X&Y describe a 2D plane and Z is the extrusion into the 3rd dimension.

 

I wouldn't mind having the extra terminology to relate IronCAD to other modeling/animation software, as long as XYZ is always referenced at the same time - so Height (z) would be acceptable.

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Guest mwalls

I would like to see it go to x,y,z myself. Anyone who is doing anything half serious needs to get it manufactured so you will be using the x,y,z anyway. I think this would be a real nice consistant thing to have through the software. Definately get rid of the roll, pan, tilt. I like the freeform ability of Ironcad which does not have to change, but I always use the xyz as a reference/orientation anyway. I agree with Mike T. on the U,V,W...Kevin, you trouble maker!!

 

Mike

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Guest EricFoy

Guys,

 

It's not that hard.

 

They go in order:

 

X - Y - Z

L - W - H

 

Figuring out the LWH was a hassle until they finally gave us the red, green, and blue axes, which now make it easy. So we expand the list:

 

X - Y - Z

L - W - H

R - G - B

 

Personally, I like the LWH notation, because it makes clear the distinction between the global system and an intellishape's local system. Otherwise, you would need something like X' - Y' - Z'.

 

I will say, however, that I've always wanted to be able to turn on a 'local grid system' for an assembly, and I would like to be able to relocate an assembly's origin to some location other than it's lower left corner - whatever THAT means - if you know what I mean. Then we could place and locate components at meaningful coordinates.

 

The next logical step (in the mind of Eric, of course) would be the ability to place a labelled datum entity (either a line or a plane) into the scene, which would transfer to the drawing just like a smart dimension, along with its label. THEN have the ordinate dimensions anchor to whichever datum you select! This would allow you to place ordinate dimensions in broken or detail views in which the anchor point is not visible. Much needed functionality in my opinion. -Should I make this an ER?

 

As for tilt, pan, and roll, THESE ARE NOT CARTESIAN MEASURES, hence they would make absolutely no sense if they were labelled x,y,z. These movements are always relative to the "heading" of a camera or light, or an object in motion.

 

Perhaps tilt should be called pitch (that's what its called in aircraft terminology), since you ONLY pitch up and down (rotationally) in the direction you are headed. You roll to the left or right (rotation), and you pan (translation) usually to the left or right, but possibly up or down as well.

 

See? simple.

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Guys,

 

It's not that hard.

 

They go in order:

 

X - Y - Z

L - W - H

R - G - B

 

See? simple.

15239[/snapback]

 

Uh... last time I checked, H>L>W and B>G>R (alphabetically speaking) wink.gif

 

And as for refrencing rotations, I'm a big fan of the good ol' rx, ry, & rz. Something easy enough that my uncaffinated brain can figure it out without wasting too many thought cycles.... you know you only have a finine number of thoughts in you lifetime, and I would rather spend mine on Pamela Anderson than converting LWH to XYZ smile.gif.

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Personally, I like the LWH notation, because it makes clear the distinction between the global system and an intellishape's local system. Otherwise, you would need something like X' - Y' - Z'.

15239[/snapback]

 

X' Y' Z' sounds good to me. I'm pretty good at decoding different symbolic systems - but given a choice, I would always prefer to not introduce a new set of symbols to signify the same basic concept as the old set of symbols. Instead, why not just relate everything to the global XYZ?

 

X', Y', Z' would work fine for local coordinates, rX, rY, rZ would work for rotations relative to global, rX', rY', rZ' would work for rotations relative to local.

 

When it comes down to it, you can choose whatever set of symbols you want - as long as you give me a Rosetta Stone. But it seems as though it would be less work for the end user if the decoding system were embedded within the symbols.

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Well I guess I will jump in here at this point. There are places where X,Y,Z will work in IronCAD, so I will concede to that point where we should look into these cases. However, there is a reason why LWH was used in IronCAD. For Example: The Sizebox of a Feature, Part, or whatever really only makes sense as LWH since it can be in any orientation (It could be XYZ but seems a little restricted for just general users to understand). You can see that we try to make it work in cases where it makes sense. For Example: If you look at the Position Property Page of a Part and Intellishape, notice that the part position is in XYZ where as the Intellishape is in LWH (I guess it could be considered the Local XYZ in this case). IronCAD initially took the stance every thing was in LWH so that the user would not need to worry about the coordinate system or local coordinate systems. We will need to revisit this but I think there will still be places where the LWH is needed unless some major changes to IronCAD core varaiables are implemented (expressions in IronCAD are based on Sizebox/Length for example).

Cary

 

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Guest EricFoy

Okay, first a little sarcasm...

 

I'll admit that the ordering of length and width requires some memorization, especially if you're not a native american english speaking person, but I think we can all agree that height *must* coincide with what would be thought of as a local Z.

 

As for RGB, who ever heard of a BGR monitor? Everyone knows it's RGB. These are the additive primary colors. I learned this in fourth grade. They are ordered in accordance with their energy level (for those familiar with quantum physics), their inverse wavelength (for those who are into radio or photonics), and it is the order in which they appear in the rainbow!

 

Honestly, you guys sound more like librarians than engineers!

 

...end of rant. please chuckle with me biggrin.gif

 

But seriously, Cary has pointed out some of the technical and historical reasons for the current notation. I would like to add to the argument in favor of the LWH notation:

 

Whereas X is both the designation of an axis as well as the holder of a value (an X coordinate), L is the designation of a distance, not a location. If you say L=12.3, you know you are talking about something with a dimension of 12.3. But if you say X=12.3 (or X'=12.3) all you really know is that the thing is 12.3 units long if its other edge sits a X=0 (or X'=0).

 

In the beginning, one of Trispectives' great strengths (and what set it apart from all the other "3D modellers") was freedom from coordinate systems and the design flexibility found in not having to worry about them. Feature positions were all determined in a relative fasion, by dragging stuff around with the triball. The architects of Trispectives hit a home run in realizing that the designer doesn't necessarily care what everything's absolute position is; rather, he really just cares how far apart stuff is. This is what makes IronCAD so great - you can just throw stuff up there and start modelling, without laying out some kind of grand plan ahead of time. Meanwhile, the software keeps track of all the coordinate systems management in the background.

 

Later, as the the product has matured (and with the introduction of the technical drafting side), the need for more direct access to the global coordinate system has been recognized. For me, the introduction of the World Coordinate Axes and the Coordinate Systems have been welcome additions.

 

But I really do share everyone's concern and frustrations with the LWH notation. I just think that the problem lies not in the notation itself, but rather in a lack of feedback offered by IronCAD. I think the L, W, and H cursor hilite while hovering over intellishape handles is great, but what I've always wanted was for All Three Arrows to be shown at the corner of the sizebox in red, green and blue. Better yet: paint the sizebox handles in their respective colors for L (red), W(green), and H(blue). They would still turn yellow when hovering over them.

 

Another cool thing would be the ability to swap length for width (without rotating the shape) this could be a right-click option on either the L or W handle. Furthermore, the ability to globally (within the scope of a part) align all sizebox lengths with either the X or Y axis of the global or assembly coordinates. Non-orthogonally aligned intellishapes would be excluded (or they could switch to the closest possible solution - this would still allow a part-wide coordination of lengths and widths).

 

I find that the coordinate feedback offered by IC is excellent when "Show Position Dimensions" is toggled on. It would be great if this mode were temporarily invoked upon right-clicking the Triball center and selcting "Edit Position." I think this would clear up a lot of confusion. However, the resulting "Edit Center Position" dialog does indeed wrongly designate LWH notation. These should be in XYZ notation, as we are clearly adjusting a position here, not a dimension.

 

A further improvement in feedback would be to place a G, A, or P at the origin of the coordinate system (as displayed when "Show Position Dimensions" is on), as an aid for the operator to know what context he is working in. It would be nice if the dialog announced the current coordinate system as well.

 

One last gripe: when right-clicking a position dimension and selecting "Edit Value," the dialog should show all three dimensions, with the focus on the one selected. This would eliminate the problem of inability to select the one you want when they are stacked atop each other on the display. Also, the dialog should say "edit Position," not "Edit Distance," but that's a fine point.

 

And now I come to my wish list: In the "Format Coordinate System" dialog, let's add two fields, Name and Label. The name would be greyed out as "GLOBAL" for the global, and user-defineable for user-created systems. The Label would transfer to the drawing in an automatically generated datum box. Voila.

 

-Eric

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Guest EricFoy

...rX, rY, rZ would work for rotations relative to global, rX', rY', rZ' would work for rotations relative to local.

15244[/snapback]

 

actually, you'll need three more to cover the translational motions too:

may I suggest tX, tY, tZ.

 

But I'm not sure you guys realize what you're asking for here.

 

We're talking about flying motion along an arbitrary curvilinear path, which may never line up with a stationary coordinate system. And if you choose to use the flying part's local coordinate system, then in order to have any consistency from one scenario to another, you must fly all your objects in the same direction relative to their "front" or "back", as predetermined by their local coordinate systems.

 

In the study of aircraft stability it is customary to place the origin at the aircraft's c.g., with X extending out the nose, Y running out the right wing, and Z pointing at the ground. Needless to say, this is not generally the same system used in designing and constructing the thing. But this layout is convenient for stability studies because it makes a pitch up into a positive motion, a yaw to the right positive, and roll to the right positive. Now for the translationals: right is positive, forward is positive, and up is negative. This is rather counterintuitive.

 

You can try both of the other coordinate system possibilities, but you will always end up with something counterintuitive, like pitching up is negative, moving forward is negative, etc. I haven't tried left-handed space yet, but I don't think we want to go there.

 

This is the problem with specifying these motions formally, and this is why it's much easier for us operators to simply learn what pitch, yaw, and roll mean. The bow of a boat pitches up and down. When you roll your car, you're not doing endos (unless your at Daytona). When you pan a camera, your sliding linearly across the floor. Strictly speaking, a Pan American jet is, in fact, panning across America -heh, heh.

 

I'm not sure, but I think tilt is a standard term used in industry for camera motions, explicitly meaning rotation about the transverse axis.

 

I would much prefer to specify "Roll to the right 15 degrees," than "Rotate about the - uh - what axis was that again?..." tongue.gif

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I think it could be good to involve some graphical prewiew of whatever axis value field is selected. Like if you are working in the anim editor and select the field "Roll" ,that rotation axis should lighten up in the graphics area making it absolutly clear for the user what the effect will be.

This could maybe be implemented in a number of places in IronCAD.

 

 

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Wow, I was just looking for a common frame of reference for similar situations that currently have different sets of symbols. I didn't realize that it might upset the aircraft industry. smile.gif

 

I do understand that L = distance along a part's X axis - and am capable of remembering that relationship for minutes at a time. I suppose I could just make a conversion chart & tape it to my monitor - but the fact that I could make a conversion chart for all coordinate systems that use three perpendicular axes tells me that it would be possible to add some helpers to the IronCAD dialog boxes to do the same thing.

 

Then I wouldn't get my monitor all sticky.

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