BodyFrame for ScriptedRotation

[mjoubert]

Hi all,

I use ScriptedRotation to send solar panel attitude. Usually, it's given in local frame. Follow the corresponding ssc definition :

ScriptedRotation
{
Module "rtorbits"
Function "rtattitude"
ObjectID "SOLARPANEL"
}
BodyFrame { BodyFixed { Center "Sol/Earth/MySpacecraft" } }

However, attitude reference frame seems to be J2000 (Earth centered). So I'm currently using a quaternion product to display solar panels properly.

My question is : Is this the expected behaviour? (maybe it's not possible to use a different frame than J2000)

Mathieu (spacebel)

[selden]

Your example uses a BodyFrame declaration which uses J2000.

Have you tried other BodyFrame declarations?

See http://en.wikibooks.org/wiki/Celestia/R ... e_property

[mjoubert]

Hi Selden,

None of other BodyFrame is correct.

When sending quaternion 1 0 0 0 to solar panel object, I'd it to "stick" the spacecraft is refering to. I cannot find a ssc definition that provide this behaviour with ScriptedRotation.

Thank you for your answer.

[chris]

Mathieu,

What you are doing should be working. The attitude reference frame should be the body fixed frame of the spacecraft. It's possible that there's some strange interaction between ScriptedRotations and reference frames. I will have a chance to test this case later today. It would be useful to see the complete ssc file that you're using.

--Chris

[mjoubert]

Code: Select all

"MySpacecraft" "Sol/Earth"
{
   Class "spacecraft"
   Mesh ""
   Radius 0.00205
   ScriptedOrbit
   {
      Module   "rtorbits"
      Function "rtposition"
      ObjectID "SATID"
      BoundingSphereRadius 10000
   }
   ScriptedRotation
   {
      Module   "rtorbits"
      Function "rtattitude"
      ObjectID "SATID"
   }
   OrbitFrame { EquatorJ2000 { Center "Sol/Earth" } }
   BodyFrame { EquatorJ2000 { Center "Sol/Earth" } }
}

"MySpacecraft-mesh" "Sol/Earth/MySpacecraft"
{
   Class "spacecraft"
   Mesh "MySpacecraft_BODY.3ds"
   Radius 0.00205
   Albedo 0.7
   FixedPosition [-0.00198 -0.000115 0.0]
   OrbitFrame { BodyFixed { Center "Sol/Earth/MySpacecraft" } }
   FixedRotation { }
   BodyFrame { BodyFixed { Center "Sol/Earth/MySpacecraft" } }
   
}

"MySpacecraft-solarpanel" "Sol/Earth/MySpacecraft"
{
   Class "spacecraft"
   Mesh ""
   Radius 0.004823
   Albedo 0.7
   FixedPosition [-0.000855 0.0 0.0]
   OrbitFrame { BodyFixed { Center "Sol/Earth/MySpacecraft" } }
   ScriptedRotation
   {
      Module   "rtorbits"
      Function "rtattitude"
      ObjectID "SATID-sp"
   }
   BodyFrame { EquatorJ2000 { Center "Sol/Earth/MySpacecraft" } }
}

"MySpacecraft-solarpanelmesh" "Sol/Earth/MySpacecraft/MySpacecraft-solarpanel"
{
   Class "spacecraft"
   Mesh "MySpacecraft_solarpanel.3ds"
   Radius 0.004823
   Albedo 0.7
   FixedPosition [-7e-05 0.0 0.0]
   OrbitFrame { BodyFixed { Center "Sol/Earth/MySpacecraft/MySpacecraft-solarpanel" } }
   FixedRotation { }
   BodyFrame { BodyFixed { Center "Sol/Earth/MySpacecraft/MySpacecraft-solarpanel" } }
   
}


[mjoubert]

If I replace SriptedRotation by SampledOrientation, everything works well.

So this problem is probably linked to ScriptedRotation.