Parameterized Lights, Directionality

[SchneiH2]

Hi everybody

I am currently working on the lights for an aircraft based on parametrized lights (reference: http://developer.x-plane.com/?article=airplane-parameterized-light-guide). Can anybody provide some help on the description under section 'Directionality of Lights' especially in terms of the last part.

I am trying to create a (directional with some cone) generic_light_sp for a tail illumination, i.e. the direction must be mainly in vertical direction with some inclination towards the tail. According to my understanding of the coordinate system for lights this will be -y direction with some +/- x component. As this type of light does not have direction parameters I have been trying to 'modify the direction of lights putting them inside an animation'. However, so far without much success. The workflow I am using is the following:

- adding a spot light in Blender (to have a direction indication)

- defining the light and adding the paramters

- rotating the spot in the necessary direction with consideration of the necessary translation of coordinates, i.e. for a vertical direction the cone of the spot in Blender must be directed along the Global positive y coordinate.

- once in the final position I just assign a Rotation-keyframe to the light.

However, it seems that I do not achieve the desired effect, i.e. the direction does not change. By changing the cone size the illuminated area changes, however, it seems that light axis always directs to the front o the plane.

Would be great to get some help.

Best regards

SHJ

[airfighter]

Check this: http://forums.x-pilot.com/topic/2611-x-plane-10-scenery-q-a/page-4#entry52308

[JGregory]

Please attach the appropriate .obj file.

[SchneiH2]

Hi Jim, hi airfighter

Thank you very much for your responses. Having looked at the content under the shown link in the post from airfighter I am not completely sure if there is some explanation to my specific issue. The point is that I believe to have understood the necessity of normalization of coordinates (dx, dy, dz) as long as these parameters are part of the particular parametric light. The light type I am using does not having them: airplane_generic_sp  R    G    B    INDEX    SIZE    W   (versus e.g. airplane_strobe_sp    R G B    INDEX    SIZE    X    Y    Z    W). To my understanding this is exactly what is being referred to under the mentioned section in the developer guide (‘All lights are modified by OBJ animation, so one way to modify the direction of the light is to put it inside an animation and use a rotation. Thus you can use an OBJ animation to ‘aim’ a light that does not have parameters for direction.'’).

 

I was trying to upload the OBJ-file but got an error message that I m not permitted to upload this kind of file. Can you advice how to proceed with this.
 

Thank you very much and best regards

SHJ
 

[JGregory]

I don't think the .obj file formats is blocked from uploads.  Maybe Cameran can explain further.  You could zip the file and post that.

[SchneiH2]

Hi

Just to give a short feedback and to close this topic (temporarily?). I have noticed that I did not correctly understand/use the Blender animation, i.e. I have used just one keyframe for animation. Indeed, at least to my understanding, an animation consist at least of 2 keyframes and the corresponding datarefs shall have two different values. Having changed this indeed the light can now be directed accordingly. The transformation of coordinates is still tricky also in relation of the cone size/effect. Needs still some work.

So far many thanks for your replies. Hope to can count on your help further!

Best regards

SHJ