Is Object3D.clearRotation() supposed to reset the scaling of the object?

If yes, perhaps we can add a note to the docs mentioning that it will clear the scaling as well.
If not, it may be a bug because scaling gets reset when calling clearRotation() even after I build the object3D before cloning it. I believe the original object3D is also affected so build->clone is irrelevant.

This was driving me nuts for an hour until I traced it to clearRotation() 

Yeah I noticed the file size difference. 100KB vs 357KB, but if it only increases the APK, it's not a problem for me since my objects are mostly low poly anyway. The APK format is actually a ZIP file so it shouldn't make much difference, zipping that 357KB serialized file shrunk it to 130KB (compared to 78KB using the 7zip format :p).

That made quite a difference, I managed to decrease the load time from 6 seconds to 4.
Cheers.

To remove an Object3D I believe you need to remove it from the world then null all references to the Object3D so the garbage collector frees it.

world.removeObject(myObject);
myObject = null;

Cloning objects wont work with objects that have different animations (every object will have the same animation timings because they use the same mesh), but you can remove triangle information from the animations by calling Animation.strip().

Ok so theoretically if the center is 0,0,0,  the lower value of the meshes bounding box should be the offset. I tried that but I'm still needing a corrective offset.

I can't seem to figure out a trending value to use. I'm guessing that calcBoundingBox() is not calculating the boundary exactly at the lowest vertex for performance reasons perhaps.


OBJECT 1
--------
Scale = 40f
Center = 0,0,0
LowerBoundingBox = -77
UpperBoundingBox = 50
Wants Offset = -10
Mesh BoundingBox 0 = -62.069466 1=51.452503 2=-33.44815 3=9.098154 4=-78.36731 5=49.07093

Scale = 80f
Center = 0,0,0
LowerBoundingBox = -67
UpperBoundingBox = 18
Wants Offset = -20
Mesh BoundingBox 0 = -124.13893 1=102.90501 2=-66.8963 3=18.196308 4=-156.73462 5=98.14186



OBJECT 2
--------
Scale = 95f
Center = 0,0,0
LowerBoundingBox = -550
UpperBoundingBox = -9
Wants Offset = 10
Mesh BoundingBox 0 = -80.026985 1=96.586525 2=-550.9481 3=-9.235985 4=-89.274704 5=144.33151

Scale = 35f
Center = 0,0,0
LowerBoundingBox = -202
UpperBoundingBox = -3.4
Wants Offset = 5
Mesh BoundingBox 0 = -29.483627 1=35.58451 2=-202.98088 3=-3.4027314 4=-32.890682 5=53.17477



By the way, there is no scaling being done loading the 3D file, there are no axis rotations (all objects point up natively), there are no animations.

obj = Object3D.mergeAll(Loader.load3DS(myContext.getResources().openRawResource(R.raw.obj7), 40f));
//obj.calcCenter();
//obj.getMesh().compress();
obj.calcBoundingBox();
obj.setTexture("obj7tex");
obj.setSpecularLighting(true);
obj.compile();
//obj.setCollisionMode(Object3D.COLLISION_CHECK_OTHERS);
world.addObject(obj);
obj.translate(mainArea.getRandomPos());
ObjectToGroundAuto(obj);

The offset seems to follow the scale so I may just calculate the offset manually at scale 100f, then scale that master offset in ratio when scaling the cloned objects.

I use a fixed height which is guaranteed to be always above the ground, calculate the distance and apply the offset to that value.

That is how I am doing it but I needed to manually supply the offset. The problem is that I have multiple instances of the object with different scales, so the offset is different each time.

private void ObjectToGround(Object3D object, float nYOffset)
{
if(terrain==null) return;

SimpleVector sv = new SimpleVector();

// Make sure object is above the terrain
object.translate(0, -200, 0);

// Get object position
sv.set(object.getTranslation());

// Determine height above terrain
float terrHeight = terrain.calcMinDistance(sv, new SimpleVector(0,1,0));
if(terrHeight == Object3D.COLLISION_NONE)
{
//Log.v(TAG, "COLLISION_NONE" );
// Drop back down
object.translate(0, 200, 0);
}
else
{
Log.v(TAG, "COLLISION terrHeight = "+terrHeight );
if(terrHeight>1000)  {object.translate(0, 200, 0); return;}
terrHeight += nYOffset;
sv.set(0, terrHeight, 0);
object.translate(sv);
}
}

And here's my current attempt to automatically get the offset, assuming calcMinDistance is based on the center of the object rather than the bounding box.
private void ObjectToGroundAuto(Object3D object)
{
if(terrain==null) return;

float fAutoOffset  = 0;


// Get mesh
Mesh mesh = object.getMesh();

// Get Bounding Box
float[] fBounds = mesh.getBoundingBox();

// Get the middle of the bounds
float fMid = fBounds[3] - fBounds[2];


fAutoOffset = fMid / 2; //(fMid * object.getScale()); // Always 1.0

Log.v(TAG,"fBounds2 = "+fBounds[2]+"  fBounds3 = "+fBounds[3]+" fMid="+fMid+" fAutoOffset="+fAutoOffset+" scale="+object.getScale());

Log.v(TAG,"Center = "+object.getCenter()); // Always 0,0,0 if calcCenter() is not called.

// Ground 
ObjectToGround(object, -fAutoOffset);
}

Are you able to show the code in the function calcMinDistance()? I'd like to see how the starting point of the object is calculated.

Ok no worries, that technique will work fine in my app if I rush the animation to zero before the sequence change.
Thanks.