@Override
public void simpleInitApp() {
setUpLight();
soldier = assetManager.loadModel("Models/Soldier/Soldier.glb");
rootNode.attachChild(soldier);
}
private void setUpLight() {
AmbientLight al = new AmbientLight(ColorRGBA.White.mult(2f));
rootNode.addLight(al);
DirectionalLight dl = new DirectionalLight();
dl.setColor(ColorRGBA.White.mult(0.5f));
dl.setDirection(new Vector3f(1f, -1f, -1f).normalizeLocal());
rootNode.addLight(dl);
DirectionalLight dl2 = new DirectionalLight();
dl2.setColor(ColorRGBA.White.mult(0.5f));
dl2.setDirection(new Vector3f(-1f, 1f, 1f).normalizeLocal());
rootNode.addLight(dl2);
}
However, it looks the model doesn’t appear correctly where mesh is broken…(screenshot attached). More strangely, sometimes it appears correctly when I tried to enable/disable lights in my code. I don’t understand why lights may affect model mesh…any enlightenment?
Part of the problem may be with “Soldier.glb”. The three.js site says it is from Mixamo, but Mixamo doesn’t provide models in GLB format, so someone must’ve converted it. Where did you get the GLB file from?
Another part of the problem may be that the model uses PBR materials. In order for PBR materials to display properly, a LightProbe should be added to the rootNode. Ideally, the light probe should be customized to your 3-D scene. However, there’s a sample light probe included in jme3-core to get you started. Here’s how to use it:
Then I downloaded defaultProbe.j3o from jme3-testdata and copied it into my project. Now I have this result which is not very different from the previous one.
Btw, After a few tests, I was able to get the correct result once I have all three lights enabled regardless I added the defaultProbe or not. However, if I disabled one light (not adding it into rootNode), I got the issue.
However, one more question. It seems the AmbientLight doesn’t work for either Soldier or the above one. They’re always black until I added DirectionalLight. Any idea…?
Is the model within the probe area of the light probe?
I’m fairly new in 3D. In my extremely limited knowledge, ambient light literally means everywhere…so maybe some links on what is light probe and how it should work?
Here is a tech paper from the nehon that implemented pbr in jme:
Part three should cover light probes.
As a summary, PBR tries to do all light calculations as realistic as possible. Ambient light as used in Phong shading does not exist in the real world. Ambient light in the real world is the indirect lighting coming from light bouncing of other objects. Even at night you have indirect lighting that comes from the sun light bouncing of the moon.
The light probe tries to capture that indirect lighting. And it requires an area because it is exact only for the place it is beeing calculated, but can be interpolated to be plausible for a larger area.
Unfortunately the lightprobes are quite expensive to calculate and it is still an area of active research on ways to calculate indirect lighting at all.
public class HelloSoldier extends SimpleApplication {
@Override
public void simpleInitApp() {
flyCam.setMoveSpeed(10f);
setUpLight();
Spatial soldier = assetManager.loadModel("Models/gltf/Soldier.glb");
Spatial xbot = assetManager.loadModel("Models/gltf/Xbot.glb");
rootNode.attachChild(soldier);
rootNode.attachChild(xbot);
}
private void setUpLight() {
DirectionalLight dl = new DirectionalLight();
dl.setColor(ColorRGBA.White.mult(2f));
dl.setDirection(new Vector3f(0f, -0.5f, -1f).normalizeLocal());
rootNode.addLight(dl);
}
public static void main(String[] args) {
HelloSoldier app = new HelloSoldier();
app.start();
}
}
By playing comment/uncomment out rootNode.attachChild(soldier) and rootNode.attachChild(xbot), I got correct result sometimes but in most time, I have broken results when soldier is attached:
Ambient light does NOT work for PBR material. Am I correct?
That depends what you mean by “work”.
Ambient light affects different materials differently. On Phong-shaded materials, the effect of ambient light is proportional to the ambient color of the material. In a similar fashion, ambient light (if present) amplifies some aspects of a PBR material and not others.
And here’s the code:
The portion of your code you’ve shared with us doesn’t add a light probe, nor does it add ambient light.
When working with PBR materials, my advice is to include all 3 kinds of light in your test scene: ambient, directional, and probe.
What I don’t understand is why I can get correct result sometimes.
I don’t understand that either, but I can imagine many possibilities.
If the Soldier model is defective, it could have incorrect bounding boxes or incorrect normals or incorrect triangle windings. There are many possibilities.
Perhaps you should work with a known-good model until you’re more familiar with the workings of JMonkeyEngine.
I’m using IntelliJ and maven, not jMonkeyEngineSDK. Not sure if there’s any pitfall related with my environment.
Many people use JMonkeyEngine with Intellij and/or Maven. I doubt either of those is causing the difficulties you’re seeing.
Thanks to everyone here. The reason I’m using models from threejs is that animations there are much better than the one we have in jme documentation (sorry , just try to learn animation a bit deeper). But for now I will follow @sgold suggestion to put this issue aside and try to get more familiar with jme with proved models.
, just try to learn animation a bit deeper). But for now I will follow 