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Object info panel & Link Editor disparity

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Object info panel & Link Editor disparity // Bugs

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Post by Alien // Jan 29, 2006, 3:57pm

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1 of the things that always bugged me about tS before v7 was that the X & Y axis seemed backwards to me. In the default perspective view X ran from top right [-] to bottom left [+], & Y ran from top left [-] to bottom right [+]. I'd hoped this would have changed this with tS7, & it seems like it partly has, but there's still have some way to go.....
http://homepage.ntlworld.com/alien42/images_for_caligari_forum/coordinateprob.jpg

<edit>
updated image to make things a bit clearer.
</edit>

Post by bill // Jan 29, 2006, 4:18pm

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I too have always had difficulty with the backwards coordinate system. I have used many different CAD and modeling programs in my 20+ years of using computers. Truespace is the only program I have ever come across that has this reversed coordinate system. If TS was the only program I used, or if in school I had learned a reversed coordinate system then it would not be a problem. One way is as good as another. But when ALL other programs have one coordinate system and TS has one that is just the opposite it makes it difficult to make the transition. If someone figures out a way to reverse it I'd definately love to know how.

Post by Alien // Jan 29, 2006, 4:50pm

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It's bad enough that they have the coordinates backwards, but the X position in the link editor is different to that in the object info panel.

Post by bill // Jan 29, 2006, 5:01pm

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I didn't even notice that. I guess that is what you were talking about in the first message. So now it appears that it is only half backwards, at least in LE. Still full backwards in modeler. I'm really going to be confused now!!!

Post by Alien // Jan 29, 2006, 5:16pm

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Probably my fault, I'm not always the best at explaining stuff. I've modified the image to make my point a bit better.

Post by Alien // Feb 2, 2006, 6:34pm

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I just had a thought - could the thing with the axis' being backwards be why textures are often 180http://homepage.ntlworld.com/alien42/images_for_caligari_forum/degrees.png the wrong way up?

Post by Norm // Feb 2, 2006, 6:52pm

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It's bad enough that they have the coordinates backwards, but the X position in the link editor is different to that in the object info panel.


Are you referring to the difference between a right and left hand co-ordinate system?


trueSpace is actually using one in model view and one in player view, hence the "backwards" coordinates.

Post by bill // Feb 2, 2006, 8:20pm

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Hey Norm. What do you mean by left hand and right hand coordinate sytems? The model view coordinate system has always confused me because it is the exact opposite of any other program I have ever used. Now player view has one that is flipped from that?

Post by Norm // Feb 2, 2006, 8:41pm

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I discovered there was a difference early on in testing. I would not rest until I figured it out. The simplest (http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/directx9_m/directx/direct3d/gettingstarted/3dcoordinatesystems/coordinatesystems.asp) explanation works best.

Post by bill // Feb 2, 2006, 8:54pm

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Hey Norm. From what I understand about left hand and right hand coordinate systems, from the page you referenced, is that the only difference is the direction of the "z" coordinate.

Quote: "Typically, 3-D graphics applications use two types of Cartesian coordinate systems: left-handed and right-handed. In both coordinate systems, the positive x-axis points to the right, and the positive y-axis points up."

In both of these coordinate systems positive Y is toward the top of the screen and positive X is toward the right of the screen. For left handed positive Z would be down and for right handed positive Z would be up. Using this definition every CAD and modeling program I have ever used uses a right handed coordinate system.

However, TS's model view uses a flipped coordinate system that does not match either of these definitions. In TS positive X is toward the left of the screen, positive Y is toward the bottom of the screen and positive Z is up. It is the flipped X and Y coordinates that have always driven me bonkers.

Post by Norm // Feb 2, 2006, 9:07pm

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Hey Norm. From what I understand


Read on Bill:

Although left-handed and right-handed coordinates are the most common systems, there is a variety of other coordinate systems used in 3-D software. For example, it is not unusual for 3-D modeling applications to use a coordinate system in which the y-axis points toward or away from the viewer, and the z-axis points up. In this case, right-handedness is defined as any positive axis (x, y, or z) pointing toward the viewer. Left-handedness is defined as any positive axis (x, y, or z) pointing away from the viewer.

Post by bill // Feb 2, 2006, 9:40pm

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I'm not saying right handed is the only way. I'm just saying it is the most common and it is the way that all of my other programs work. That is why the TS coordinate system confuses me.

I've been working with CAD and modeling programs for over 20 years. I spend my days drawing and modeling house plans. Right now TS is just a hobby and a tool that I occasionally use to make some 3d model elements for my architectural plans. I use whatever program gets the job done the fastest. I exploit the strengths of each program and combine all the results into the final product. For me TS is is the program I use to create smooth shapes such as an old fashion bathtub or a special sink bowl. I use Sketchup or TurboCad to model most detail elements. I draw my plans using SoftPlan. I draw site plans in TurboCad. And I use Autodesk Inventor to model machinery, I'm always working on an invention of some sort or another. I even have AutoCad but I rarely ever use it for anything other than as a conversion program.

The main reason I don't use TS more is because of the reversed coordinate system. Having to reverse the coordinate system in my head is extra thought overhead I can do without.

Post by Norm // Feb 3, 2006, 6:49am

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... Having to reverse the coordinate system in my head is extra thought overhead I can do without.

I understand your sentiments.

To be honest, I see no reason why a simple script could not be written to overcome the scenario bill.

Post by bill // Feb 3, 2006, 7:49am

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Norm, if such a script were made available I'd be truely grateful. I appreciate your listening to all my ramblings. :)

Post by Norm // Feb 3, 2006, 7:56am

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Not at all bill.

The developers put up with my ramblings on same subject during beta testing :)

Post by Alien // Feb 4, 2006, 2:50am

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All this talk of left & right-handedness has got me a little confused, even after trying to make sense of that MS article. :( So I came up with this:

http://homepage.ntlworld.com/alien42/images_for_caligari_forum/different%20axis.png

Post by ProfessorKhaos // Feb 4, 2006, 4:47am

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Hi Alien,


Close but not quite. Actually both of your systems are the same one but rotated about the z axis. Just invert the sign of one of your X and Y axis, not both.


Here's a slightly corrected version (I assume you're looking down at the origin of the system from slightly above)

Post by Alien // Feb 4, 2006, 5:04am

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Yeah, but neither of those is what I want. As for viewing position, I'm talking about the default view for perspective view. My image was correct in the sense that the 1 on the left is what model view in tS has always been, & the 1 on the right is what I want.

Post by ProfessorKhaos // Feb 4, 2006, 5:07am

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Ah... ok. That makes sense. So basically you want a right handed system where the -X and -Y axis face towards you by default, not away. It does sound like a simple script linked to a new "default perspective view" button would be a good fix.


<edit>

Sorry, guess I was following along with the original post and assumed that's what your latest was about. The original was a right handed vs left handed system issue. My bad! :)

Post by Alien // Feb 4, 2006, 5:11am

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If I understand correctly your pictorial explanation of handedness as it pertains to 3D coordinates, then yes.

<edit>
& as for subject, it kinda mutated from 1 to the other.

Norm: thanks to the Prof's explanation, I think I now get what you mean, but the prob was I wan't on player view, I was on model view. I understand that the LE is more tied to the player than to model view, but when just the model view's being shown [as opposed to something like the dual view], surely the LE should adapt to match the model view?
</edit>

Post by ProfessorKhaos // Feb 4, 2006, 5:25am

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BTW Alien, congrats on reaching senior member status :)


With that many posts I think you must be somewhat sleep deprived though! :)

Post by Alien // Feb 4, 2006, 5:27am

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LOL, not really. :) & thanks.

Post by bill // Feb 5, 2006, 6:10am

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Norm, I believe I have a solution. Is there a way to redefine the standard views? The TS coordinate system would work the same as all my other programs if the views could be redefined as follows:

1) Rotate the Top view 180 degrees around Z.
2) Switch the Left and Right views. Current Left becomes Right and Right becomes Left.
3) Switch the Front and Back views. Current Front becomes Back and Back becomes Front.
4) Rotate the Bottom view 180 degrees around Z.
5) Make the same changes for the "Small" views

If all the Views could be redefined then the coordinate system is effectively rotated 180 degrees and matches all of my other programs. Is there a way to do this? Of course if the Player view were modified to open as initially rotated 180 degrees as well this would be optimal.

If this can be done, where would I start looking to find out where these views are defined?

Post by smoothchat // Feb 5, 2006, 2:15pm

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Would this need to be a "toggleable" option?


I mean, wouldn't any previous version object/scene animations playback back to front?

Post by Alien // Feb 5, 2006, 2:19pm

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Hmmm... You raise an interesting point. 1 idea would be that if it's possible to create a script to do as Bill described, perhaps someone could create a script to automatically convert/rotate/modify older scenes that have been imported to tS7.

Post by kujisha // Feb 5, 2006, 3:06pm

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Wow, I never noticed this. Hummm, very interesting!:eek:

Post by stan // Feb 5, 2006, 3:34pm

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this won't help Bill, but in visual terms this is what the axis look like in model vs player..a script would only have to make +X values into - and -X values into +..

Post by bill // Feb 5, 2006, 4:06pm

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Hey Stan. Personally I don't care what the axis is in Player. My only problem is trying to model with the axis reversed from what I am used to. In perspective view I can rotate the scene 180 degrees around Z and vloila...everything is good. But then if I switch to one of the predefined views such as Front, Left, Right, etc. everything is backwards to me. So if I had the ability to switch these views around so Front is changed to Back and Left is changed to Right and both Top and Bottom are rotated 180 degrees all would be well. This won't change the axis nor will it change the coordinate system. And it would not affect animations either. All it would do would allow me, and others like me who are used to looking at 3D worlds in a certain perspective, to maintain that perspective. Nothing would be changed other than how I view the model.

To illustrate what I'm talking about imagine that someone gave you a pair of glasses that reversed everything you see. The world has not changed, only your perspective of the world. Left is now right and front is now back. Now try driving a car with these glasses on. That is my problem. If I could reverse the perspectives all would be well.

Post by stan // Feb 5, 2006, 4:19pm

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I realized that Bill..that's why my post started with "this won't help Bill"..Alien mentioned bringing old scenes up to spec..

I understand your dilemma..it has to do with world axis/view relationship..if you could only choose which way it was oriented as a preference..then front would be front and not need to be reversed with back..

Post by bill // Feb 5, 2006, 4:44pm

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But my point is that there is no need to rotate or reverse anything in the model or animations. Initially I was thinking in terms of rotating the axis 180 degrees around Z. This might cause problems with animations and such.

However, the more I thought about it and looked at it I came to realize that the axis was not the problem. The problem was one of perspective in the predefined views. Modifying the perspective of the predefined views only changes the way you look at the model in these views. The actual model and scene is unchanged so there is no need to "bring old scenes up to spec". The axis and coordinate system is still the way it has always been. Only how you look at this coordinate system in the predefined views would need to be altered.
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