Rotation handle bug?

Started by Hannes, October 28, 2021, 05:10:29 AM

Previous topic - Next topic


In my recent work I used a space station with kind of "wheels" which is originally in an upright position. Since I wanted to create a flyby along its rotating rings I rotated the whole object by 90° along its x-axis to easily move the camera along the model.
But after I did that, the green rotation handle was gone, and it was impossible to make the "wheel" rotate. Even typing in values didn't work. Changing values in the y- and z-axis produced the same rotation.

Whereas if you initially rotate the model by 90° using the z-axis, all the handles are there, and you can rotate the wheel.

I attached a simple example file for testing: rotate the model 90° along the x-axis and then try to rotate the wheel.


I thought at first if this is a gimbal lock problem but in my old 4.1.25 version of Terragen i have no problem rotating the object.
Maybe a problem in the newer version?


Thanks Kadri! Just tried it in V. 4.4.49, and it's not working either.


Hi Hannes,
doesn`t 3DSMAX have a z-up coordinate system?
If you tick "Source Z up" on the Obj Options tab you should be good, I think.
The Ring "stands up" and animating the rotation in all three axes is possible.
The Ring obj in the scene has the y-axis lying flat / horizontally when I open the file in TG.

But it is actually quite possible that I don`t understand the problem...

I`m on 4.5.56.

CHeers, Klaus

ps: from the Wiki:
A solid line is drawn to show the axis of rotation for each circle.
A blue dotted line is drawn to show the object's positive X axis,
which can help show the object's orientation in space.
/ ASUS WS Mainboard / Dual XEON E5-2640v3 / 64GB RAM / NVIDIA GeForce GTX 1070 TI / Win7 Ultimate . . . still (||-:-||)


Quote from: KlausK on November 02, 2021, 11:52:45 AMdoesn`t 3DSMAX have a z-up coordinate system?
Yes, it does.

Originally my object is upright. In the TG scene I rotated it by 90° along the x-axis, so that it's "lying". And the green rotation angle was gone. If I rotate it by 90° along the z-axis, everything is there. This doesn't seem correct to me.
Of course I could reload the object in Max and change its orientation, but nevertheless it's strange, that you can't spin the wheel, if you don't. Even by typing in values!
Why is one handle gone, after I changed the x-value, but not, when I changed the z-value?


It is not gone. You rotate the x-plane on top of the y-plane. Which is the horizontal plane - which is wrong in terms of TGs axis system. And you are left with still 3 axes but only two planes to rotate. The Source z-up fixes that. No need to go back. That is why I thought the Wiki qoute is helpful.
When you rotate over x (the red circle) the positive x of your object and the y of TG space overlap / are on top of each other.
When you rotate over z --> the blue circle nothing overlaps. The objects positive x now points downward and you can see and rotate all of the rot axes.
That is at least how I understand it.

CHeers, Klaus
/ ASUS WS Mainboard / Dual XEON E5-2640v3 / 64GB RAM / NVIDIA GeForce GTX 1070 TI / Win7 Ultimate . . . still (||-:-||)


Quote from: KlausK on November 02, 2021, 01:21:09 PMIt is not gone.
Yes, I saw, that it's hidden by the other plane. But somehow it's weird, that I can't rotate the wheel or even type in some rotation, whereas I can, if I initially rotate the object by the z-axis.

Actually it's not the end of the world of course. ;)
The only thing that bothers me, is that I can of course rotate objects the way I want in other apps, no matter, what their initial orientation is.

Anyway, thanks for your help, Klaus!!!