# How to calculate the trajectory of an object under rotating thrust?

#### weirddave

The for loop with a smaller timestep:
Code:
Temp_Ship_ms = 1000; /* this is for pullling out the 1 second positions */
for (int i = 1; i < 6000+Frame_Time; i+=Frame_Time){
Compute_Obj_Position(Temp_Ship, Frame_Time); /* move the ship forward in time by Frame_Time */
if i >= Temp_Ship_ms {
Draw_Obj (Blob_Obj, Temp_Ship.X_pos, Temp_Ship.Y_pos);
Temp_Ship_ms += 1000;
}
}
But the best option is romseks maths in the position compute code and call that for the prediction as well with 1 second increments.

#### DangerFace

@weirddave Thank you for diving further into this. The ship code would not be using the math to actually move. Unity has methods wrapped up in it's physics module that I could.. unpack to see what they are actually doing. The physics calculations get called during a specific part of Unity's monobehaviour loop - "FixedUpdate".

I may end up needing to try your suggested route. I'm going to spend some time today attempting to get the formula working to show course prediction. I'll post results when I have them.

In the meantime, I thought I would share a couple of screenshots showcasing the way this works, just in case you are curious. The full images are attached.

You set your acceleration force and your target rotation at the start of a turn. Then watch 6 seconds of the ship operating under those forces.

#### weirddave

A quick google suggests there are at least 2 update methods, 'FixedUpdate' and 'Update'
I would be tempted to try and manipulate one or both of those. If I've understood correctly, if the objects have those methods then they get updated, so I would be looking to enable/disable this for the objects (so I can apply the update to just my copied ship to get the future coords) and also looking at where these updates get their time info from and manipulating that.
The alternative is to ignore those and write your own
Keep us posted, this is most interesting.

#### weirddave

I guess you've seen this?