How to add light to a model properly?

Hi my aim is to add a scene to my simulation in Jmonkey. I created a very basic mesh in blender (simple cube with roof removed and a face removed). When I import it in Jmonkey and add a directional light to it, it appears completely dark from inside. I have removed its roof as well and tried various directions for the light but all in vain. How should I make it illuminate from inside as my whole scene is inside the box.

PS: I want to give a room effect (a room scene basically)

Going by this:
http://hub.jmonkeyengine.org/forum/topic/how-to-decide-direction-of-directional-light-for-a-model-in-jmonkey/

Your light is only affecting the model, the light needs to attached to a node which is parented to the whole scene.

I have ambient as well as directional light attached to the rootNode as well…

[java] private void setUpLight() {
// We add light so we see the scene
AmbientLight al = new AmbientLight();
al.setColor(ColorRGBA.White.mult(1.3f));
rootNode.addLight(al);

DirectionalLight dl = new DirectionalLight();
dl.setColor(ColorRGBA.White);
dl.setDirection(new Vector3f(2.8f, -2.8f, -2.8f).normalizeLocal());
rootNode.addLight(dl);

}[/java]

Still have a black model from inside, its walls outside are illuminated well…

Are your walls made out of quads? (they have no thickness?)

Perhaps show a picture of it in Blender, and what it looks like in jME

I made a cube, deleted one of its faces (and roof as well). Thats it
have I done it wrongly??

yep, only front faces are shown by default in jME. You can confirm this by doing:

[java]room.getMaterial().getAdditionalRenderState().setFaceCullMode(RenderState.FaceCullMode.Off);[/java]Note: this assumes room is a geometry

But instead, extrude the faces in blender or use the thicken modifier.

Ya that seem to work. Thanks
But extrusion only moves the faces, it does not solidifies faces as in google sketchup Move tool…

I have tried make the walls solid using extrusion tool (move tool in sketchup). However I still face the same problem.The problem is that how should I decide which face of the surface will illuminate and which will appear black.

I have attached screenshots of jME and Google sketchup model…
Please help… Screenshot

Managed to solve the problem. These was a problem with the export tool I guess.

While using Google sketchup

  1. When I export the model in obj format, some faces appear black.
  2. When I export the model using Orge XML, it works perfectly…

Using Blender

  1. Using obj format, it appears black
  2. I have not tried any other thing