Possible FPrime Problem


Does anyone know if this is a bug?

Working with a scene that has a spacecraft that is parented to a series of nulls: one controls motion, its child controls Heading, a child of that controls Pitch, a child of that that controls Bank, and one last child: the spacecraft, which has no animation at all. I work this way because for me at least it makes it easier to animate flying vehicles. I never use align to path becasue I don’t like the results.

When I render with F9(built in renderer) all is well: the plane appears exactly where I want it, with heading, pitch and bank all correct.

If I choose FPrime, it is tilted completely the wrong way. This is repeatable with this scene, but I want to see if I can get it to happen in another scene. It will happen in both LW[8] and 7.5c.

I’m thinking maybe FPrime calculates rotation orders differently than LW? Thats the only thing I can think of, but the folks at Worley wouldn’t make a mistake like that.

Here is a screen grab


This is most likely the reason because LW evaluates parent rotation in wrong order. Funny thing is that LW is the only program in the world that does it wrong and it seems like Steve has used the normal (which is also the right) way to do the rotation evaluation. It’s not that something would’ve done horribly wrong, it’s just that it’s been made in wrong order.


You have had the same experience?
I was just about to use FP on a good sized render. Oh well.


I don´t think so, I´ve tested here and I don’t have problems with that until I move the camera, but if I press Refresh, FPrime updates the window correctly.



But if the resultant render is wrong(as in the Photo I supplied)
and it turns out that you can’t even use the plugin you bought to make up for LW’s shortcomings, bad AA, motion blur and general render slowness—I’d say that qualifies as horribly wrong.
Hopefully its my human error, but the setup I have is simple…If I rearrange the nulls to match the rotation order used by the rest of the 3d world, then it should solve the problem.



i’ve got the same problem… only with 2-3 objects in the scene…
when i turn my camera around the main object, Fprime don’t “accept” the
rotation of the camera and stay at the initial position in the scene…

strange, very strange…


Is your setup like this?:







Is this way:








In short: I’m part of LW-fin user group. We have experienced everything possible.

I’m not sure but rearranging the nulls could help…or maybe even adding the FPrime displacement plug-in to each of the nulls will do the trick.


But tonight it will take more than adding the FPrime displacement plugin to make this work. Since Lightwave’s rotation order seems to be H(Y),P(X),B(Z) then maybe using another cobination will work. What is the standard anyway? ZXY?


Sorry my confusion. When you say ZXY, do you refer to direction that aims the arrows of rotation Handles?

If this way my setup is:

Heading_Null ( Z )
Pitch_Null ( Z )
Bank_Null ( Y )



Wherever the problem may be located, I’d suggest using either Pointoven or Displacement Baker, or even LW’s own MdScan, to bake out the world motion of the vertices in your mesh. That way, u can do away with the entire parenting tree and any other motion modifiers u might be using, and have a clean scene for render and lighting. Don’t forget to apply the Fprime displacement plugin to the object.


try turning on FSPE just before rendering, I had similar problems and the was the only solution apart from baking everything


What is FSPE?
I have no idea what it could be…


open the options panel (o) and hit f

FSPE stands for Ful scene Parameter Evaluation, more about it on the Worley FPrime manual
Makes working with LW pretty useless as it can really slow thing down or stop them completely, but can be OK to turn it on just before rendering, when all the staging / animation is finished.


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