jMonkeyEngine.org

Just use empty nodes to place the motion path points later along where they are?

like I said, ad some marker nodes and use their location:

Spatial markerSpatial = level.getChild("MyMarkerNode1");
path.addWayPoint(markerSpatial.getWorldTranslation);

(obviously you should automate the name search)

You can also try a brain-to-computer interface and just imagine your level..

You can also try a brain-to-computer interface and just imagine your level..

Hah, oh how I admire a dry wit. But my killer-game* idea involves moving the camera along a large number of detailed paths; to hand-code or simply whip up a few splines in Blender? Hmm… Thanks for your suggestion though.

And thanks nehon… Surely I’m not the only person to have needed to import paths so far!? It might be quicker in the long-run if I write a little python script to export the data I need. I’ll let you know how it goes.

THanks guys!

I don’t get whats the issue

I would like to have been able to define motion paths by DRAWING them in Blender, over and around the objects in my scene, then upon importing the scene telling JME to “use the points in these splines I’ve drawn as a camera motion paths!”

Defining individual objects in Blender for waypoints is a workaround (that I”m using right now, thanks!) but it means that i) I can’t actually SEE the paths in blender (just the points), ii) I have to manually manage disparate objects (one for every waypoint!) and iii) manually manage the names of the objects to indicate which ones belong to the same path, and their order.

I will investigate the python script solution so that I can scrape my Blender scene for the splines I have drawn, export their vertices to a file, then import into my JME application to be used as the waypoints in motion paths.

As for what I’m trying to achieve, I want a navigation system in which the user clicks on an object/location, and, via a series of *pre-defined* motion paths, moves to that object/location. I will need a lot of (complex) motion paths to navigate from location to location in the environment.

I would do path in blender, export .obj (no material needed, not even faces needed), load it with own loader and setup these vertices.

# Blender v2.61 (sub 0) OBJ File: ''
# http://www.blender.org
mtllib path.mtl
o Plane
v -0.347565 0.000000 -2.461765
v -1.000000 0.000000 1.000000
v -1.000000 0.000000 -1.000000
v 0.840120 0.000000 -3.238328

String str=LoadTXT("test.obj"); // reads whole file to string
String[] lines=str.split("n");
for(int line=4;; line++)
{
   if(lines[line].charAt(0)=='f') break; // if face, leave
   String[] val=lines[line].split(" ");
   Vertex3f pos=new Vertex3f( parseFloat( val[1]), parseFloat( val[2]), parseFloat( val[3]) ),
   path.add(pos);
}

Something like that.

For what it’s worth, I ran into trouble with the .obj export as well, so invested a bit of time with the python script.

The following addon script exports selected paths in Blender as java source code which can be copy-pasted directly into my class, but could easily be customised if anyone else would benefit from such a thing…

bl_info = {
    "name": "export paths 1.0",
    "author": "Tai Po",
    "version": (0, 1, 0),
    "blender": (2, 5, 9),
    "api": 37702,
    "location": "File > Export > Export Path Data",
    "description": "Export points in paths",
    "warning": "",
    "wiki_url": "",
    "tracker_url": "",
    "category": "Import-Export"}

import os
import bpy
import io
import mathutils
from math import radians
from bpy.props import StringProperty, EnumProperty, BoolProperty

class TestExporter(bpy.types.Operator):

    bl_idname = "export.test"
    bl_label = "Export Paths"
    filepath = StringProperty(subtype='FILE_PATH')

    # This is called first. It will open the file selector; after the user
    # selected a file, execute(self,context) is called.
    def invoke(self, context, event):
        if not self.filepath:
            self.filepath = bpy.path.ensure_ext(bpy.data.filepath, ".txt")
            WindowManager = context.window_manager
            WindowManager.fileselect_add(self)
            return {"RUNNING_MODAL"}

    # Called by the file selector
    def execute(self, context):
        filepath = self.filepath
        self.save(context, **self.properties)
        return {"FINISHED"}

    # Save the file
    def save(self, context, filepath=""):
        if os.path.splitext(filepath)[1] == '':
            filepath += ".txt"
        f = io.open(filepath, mode="wt", newline="n", encoding="utf_8")

        obs = bpy.context.selected_objects

        for ob in obs:
            f.write("thePaths.put("%s"," % (ob.name));
            wmt = ob.matrix_world
            splines = ob.data.splines

            f.write("new float[][]{");

            for spline in splines:

                lastindex = len(spline.points)-1
                for index, pt in enumerate(spline.points):
                    co = pt.co * wmt
                    f.write("{%ff,%ff,%ff}" % (co.x,co.z,-co.y));
                    if not(index == lastindex):
                        f.write(",")
                f.write("}");
                f.write(");n");            

        f.close()

def menu_func(self, context):
    self.layout.operator(TestExporter.bl_idname, text="Export Template (for test)")

def register():
    bpy.utils.register_module(__name__)
    bpy.types.INFO_MT_file_export.append(menu_func)

def unregister():
    bpy.utils.unregister_module(__name__)
    bpy.types.INFO_MT_file_export.remove(menu_func)

if __name__ == "__main__":
    register()

(NB: Blender uses a different coordinate system to JME, so you have to swap the Y & Z axes, and make the Z value negative.)

… and here’s an example of the output (I’m using custom PathManager and PathDef objects to build & manage the MotionPaths)

        thePaths.put("Path2",new float[][]{{0.552299f,-3.205562f,0.000000f},{1.772858f,-2.669704f,-0.456506f},{2.050186f,-0.636155f,-0.963735f},{4.234775f,-0.129691f,-0.456506f},{4.682837f,2.490573f,0.000001f}});
        thePaths.put("Path1",new float[][]{{-2.922342f,3.740610f,-0.000000f},{-1.691757f,3.228198f,-0.456506f},{-0.029767f,4.432367f,-0.963735f},{1.845480f,3.202577f,-0.456506f},{4.049649f,4.688573f,0.000000f}});
        thePaths.put("Path3",new float[][]{{-4.455926f,2.620504f,-0.000000f},{-4.434050f,1.287676f,-0.456507f},{-2.666182f,0.245144f,-0.963736f},{-3.044405f,-1.965259f,-0.456507f},{-0.801575f,-3.392234f,-0.000000f}});