How to Create a Mesh from Cloud Points

newto3d · June 14, 2011, 9:17pm

I have gone through the tutorial hereHow to create a Mesh and had no success in doing the following task.

I have a cloud points (x,y,z) file which has thousands of points. How do I plot those points in JME? How should I approach ?

newto3d · June 15, 2011, 4:06pm

I have the following code which creates a MESH in a point mode which draws point at each vertex. However, it is only drawing one point instead of 4. What could be the problem? With the sample example I was able to draw all four points! But not with my custom values. What am I missing in the code? please help!!! Thank you!

pre type="java"
Mesh m = new Mesh();



Vector3f [] vertices = new Vector3f[4];

        vertices[0] = new Vector3f(26.354990f,40.326794f, 0);

        vertices[1] = new Vector3f(36.938738f, 50.282257f, 10);

       vertices[2] = new Vector3f(46.516779f, 60.237816f, -20);

       vertices[3] = new Vector3f(56.126751f, 70.237816f, 30);

         m.setBuffer(Type.Position, 3, ufferUtils.createFloatBuffer(vertices));

        m.updateBound();

   // Creating a geometry, and apply a single color material to it

        Geometry geom = new Geometry(“OurMesh”, m);

        m.setMode(Mesh.Mode.Points);

        m.setPointSize(1f);

        m.updateBound();

        m.setStatic();

        Material mat = new Material(assetManager, “Common/MatDefs/Misc/Unshaded.j3md”);

        mat.setColor(“Color”, ColorRGBA.Green);

        mat.getAdditionalRenderState().setFaceCullMode(FaceCullMode.Off);

        geom.setMaterial(mat);

        // Attaching our geometry to the root node.

        rootNode.attachChild(geom);
/pre

baalgarnaal · June 15, 2011, 4:12pm

this may sound a tad silly but have you tried lowering those values? It’s not impossible that those values simply are not in the camera’s view, whereas the example keeps them at 0 to 1 everywhere…

Ogli · June 16, 2011, 2:58pm

Why not use a factor like 0.1f vor all those values?

Did you set the near clipping plane, far clipping plane and camera position accordingly?

Also: Be aware, that Float (EEE single floating point) only gives 6 to 7 decimal digits of precision…

newto3d · June 16, 2011, 3:06pm

Instead of using Quad Mesh to draw the cloud points, I am now using BOX. Also, I have cloud points file with 2 Million+ points!!! The application hangs at just about 200k points!! Can JME handle these many points in some way? Here is my code

pre type="java"
//for every cloud point(vector). This is inside a for loop.

boxMesh = new Box(vector, 0.1f,0.1f,0.1f);

geometry = new Geometry(“sphere”, boxMesh);

geometry.setMaterial(solidColor);

geometry.setCullHint(CullHint.Dynamic);

rootNode.attachChild(geometry);
/pre

In the end, after the for loop I have

pre type="java"
cam.setLocation(new Vector3f(0, 0, -5));

cam.lookAtDirection(Vector3f.UNIT_Z, Vector3f.UNIT_Y);

cam.setFrustumFar(1000);
/pre

Is there a way to make JME run well with 2+ Million cloud points(Box) ?

Ogli · June 16, 2011, 6:35pm

Would you like me to implement an LOD-Viewer for your point cloud?

Seems like a good exercise.

It would be a combination of an LOD-graph and visualisation techniques.

Could you just give me the max(x,y,z) and min(x,y,z) ? then I will generate the points randomly for the test.

newto3d · June 16, 2011, 6:57pm

Ogli said:
Would you like me to implement an LOD-Viewer for your point cloud?
Seems like a good exercise.
It would be a combination of an LOD-graph and visualisation techniques.
Could you just give me the max(x,y,z) and min(x,y,z) ? then I will generate the points randomly for the test.

That is so nice of you!! Here are the MAX and MIN...
MAX(5.847956, 2.126556, 19.251)
MIN( -4.675392, -3.287754, 0.0)

Thanks!!!

Ogli · June 16, 2011, 10:07pm

Ok, I will report the progresses in this thread.

I was quite skilled with jME2, jME3 is a bit new to me.

So maybe it will take some days instead of hours…

Ogli · June 26, 2011, 5:08pm

Here the first results:

PointCloudJme3GraphGenerator.java - interface

AbstractPointCloudGraphGenerator.java - implementation, part 1

RawPointCloudGraphGenerator.java - implementation, part 2

TestPointCloud.java - a simple test application (2 mio. random points)

Even with this very early brute force technique I get maximum framerate on my 2 year old machine.

I simply used point sprites - and the hardware culling speeds things up, as I have seen during the test.

Only thing that I struggled with, and could not fix yet: the points appear as semi transparent. I would have liked them to be totally opaque.

Also, they are currently squares, not circles. This is by design and could be fixed easily. There are two options for a fix: Write a simple shader with (uu + vv) > 1.0 = transparent, or simply use the particle material with a texture, that shows a circle. As I just said - both very simple ways to turn squares into circles…

8)

Ogli · July 10, 2011, 5:54pm

Hm, no feedback…

Seems there is no interest in point cloud visualisation anymore.

So there is no motivation for me to spend time on this.

Hope, the solution from my previous post helped anyone…

bye

normen · July 10, 2011, 7:13pm

Point clouds work fine:

http://code.google.com/p/jmonkeyengine/source/browse/trunk/engine/src/test/jme3test/effect/TestPointSprite.java

Ogli · July 10, 2011, 7:50pm

It has not been the task of the original poster to generate a particle system.

What he / she had in mind was the visualisation of a cloud of points with specific coordinates.

You can look at the posting before yours - I posted 3 classes / interfaces, and a simple test…

normen · July 10, 2011, 11:15pm

Since the particle system was lately extended by an influence system it would be no problem to implement that. In fact it really wasn’t before.

Ogli · July 11, 2011, 9:51am

The original poster could not accomplish it, so I helped out.

If there had been more interest, I would have continued with spatial partitioning and LOD.

The only reason my simple brute force test worked, is because there were “only” 2 million points to be rendered.

And I too had difficulties: If I hadn’t had knowledge about GLSL shaders I would have failed to use the particle shader.

kotoko · June 29, 2012, 4:41pm

I’m late but this would be very useful for me, can I use it?

zarch · June 29, 2012, 7:05pm

You might want to message @ogli directly, I doubt he’ll notice a forum post nearly a year later

Ogli · July 2, 2012, 8:55am

Hello kotoko and zarch:

Yes, the point cloud renderer is open-source with the same license like jME.

Feel yourself free to use it! (and even better: to modify it yourself)

jappinen · July 24, 2012, 6:59pm

I wouldn’t mind testing any new developments with this code… sorry I wasn’t here to appreciate your work here a few years ago Ogli.

sbook · July 24, 2012, 7:08pm

If someone wanted to pick this up, it would certainly be a nice addition to the contribution repo

jappinen · July 25, 2012, 3:41pm

Ogli, what were your ideas for extending your LOD viewer? I am enjoying it.

Here are a few things I would like to get working:

Point Size - on a per vertex basis - possibly calculated as a function of existing data or some other data.
Animation - new data (position, color, pointsize) per frame… or interpolation between keyframes, data deltas, or whatever.
Other “tracks of data” to be used on a per vertex basis (available to custom “render” callbacks, or made available to shaders)…
Support rendering 2d/3d textures in addition to vertex buffers.
Grid System

axis, labels, coordinate tracking,

mouseover point descriptions (listener approach… default behaviour do nothing)

if data was denormalized… methods to convert points back to original data values… i.e. pluggable functions.

Data culling/volume probe – like in the glman pointcloud demo.
cutting planes/etc.

Some of this can be stuff can be pushed into shaders… perhaps a flexible architecture to decide what is done where… Or just different implementations…