Rotation Question 
Author Message
 Rotation Question

I have a map that the user needs to be able to rotate.  I don't want to use
a SphereSensor because I need to put limitations on the rotation.  Ideally,
only let the user rotate the map in a semi-circle that is defined by the
users position or in other words, always keep the map in a readable position
from the users point of view.  Once the viewer has moved to a different
point they should still be able to rotate the map, but the coordinates of
the semi-circle will be different.

My first thought is that is I could get the normal of the map then I could
find the angle between the viewpoint and this normal.  While I can find the
normal, the coordinates of the map change as the user rotates it and I am
having trouble with the math.

So, does anyone have an example, a better idea, or a pointer to material
that will help me out?

thanks,

Jim



Tue, 29 May 2001 03:00:00 GMT  
 Rotation Question
Have you considered defining the object as a billboard?
Billboards always have the same side facing the avatars viewpoint.

-TUCO-

Quote:

>I have a map that the user needs to be able to rotate.  I don't want to use
>a SphereSensor because I need to put limitations on the rotation.  Ideally,
>only let the user rotate the map in a semi-circle that is defined by the
>users position or in other words, always keep the map in a readable
position
>from the users point of view.  Once the viewer has moved to a different
>point they should still be able to rotate the map, but the coordinates of
>the semi-circle will be different.

>My first thought is that is I could get the normal of the map then I could
>find the angle between the viewpoint and this normal.  While I can find the
>normal, the coordinates of the map change as the user rotates it and I am
>having trouble with the math.

>So, does anyone have an example, a better idea, or a pointer to material
>that will help me out?

>thanks,

>Jim



Thu, 31 May 2001 03:00:00 GMT  
 Rotation Question
Hi Jim,

I think I know what you mean, check out this URL to see if I do...
http://www.geocities.com/Area51/Dimension/8756/mAnimator.wrl
Use the big gold dial in the top right corner to reposition the
viewpoint (drag it)

If this is what you're after, let me know and I'll explain how I did it.

South



Fri, 01 Jun 2001 03:00:00 GMT  
 Rotation Question
I don't want to use a billboard because I want to user to be able to rotate
the map.

Jim

Quote:

>Have you considered defining the object as a billboard?
>Billboards always have the same side facing the avatars viewpoint.

>-TUCO-



Fri, 01 Jun 2001 03:00:00 GMT  
 Rotation Question
Thanks for your reply and that a cool app.  But it not exactly what I am
looking for or maybe it is and I am not getting it.  Here is an explanation
of what I am looking for.

Say you have a map with a bubble over the top of map.  So that this bubble
is a hemisphere.   You can rotate the map up and down and maybe turn it like
a turntable.  But if the edge of the map touches the bubble the rotation
would stop.  Now let the user move his viewpoint.  What I want to do is to
rotate the bubble and map to face the user, then let the user rotate the map
inside the bubble as describe above.  The tricky part for me is that the
bubble is now a totally different set of coordinates and a stated before my
math stinks.

I also need to mention that I have my own HUD to let the viewer control
their movement as well as that of the map so collision detection do not seem
to work.  A thought I had was to put invisible planes around the map and
when the map intersected them route that to a script.  But I not sure how to
get the intersection event.

I am thinking that I need the use a Matrix, so that I can found the
coordinates of the map once it has been tranformed, but once again my math
is awful and I am having trouble with this.

Jim

Quote:

>Hi Jim,

>I think I know what you mean, check out this URL to see if I do...
>http://www.geocities.com/Area51/Dimension/8756/mAnimator.wrl
>Use the big gold dial in the top right corner to reposition the
>viewpoint (drag it)

>If this is what you're after, let me know and I'll explain how I did it.

>South



Fri, 01 Jun 2001 03:00:00 GMT  
 Rotation Question

Quote:

> I am studying butterfly flying simulation.but I have a question.
> I use 3DMax build a butterfly model .Then use OrientationInterpolator to
> rotate
> the butterfly's wing.But the wing  will not rotate on one indexfaceside.

> Can anyone solve it..

It looks like your center is off a little.  What you need to do is
either put a center field in the transform you're animating, or else
wrap it in another transform where you translate the hinge point to
zero and then animate the outer transform.  I usually do the latter,
but everybody tells me it's the hard way.

That's a really nice butterfly, btw.  It's going to look very good
when you put the textures on it.
--
Bob & Kelly Crispen

"And I observe, when any Yahoo comes from London out of Curiosity [to]
visit me at mine own House, we neither of us are able to deliver our
Conceptions in a Manner intelligible to the other."



Sat, 02 Jun 2001 03:00:00 GMT  
 
 [ 6 post ] 

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