I have a problem about how .intersectLine works in three.js
I have a line (line) and a plane (planoref) , and I want to know the point of intersection.
new THREE.Vector3( planoref.intersectLine(line));
but the response was: planoref.intersectLine is not a function"
How does this function work?
How can I know the point of intersection of a line or ray with a plane?
Thanks
Your code probably contains an error, or perhaps you are using an outdated version of three.js. The following code fragment works and outputs the expected "5".
var line = new THREE.Line3(new THREE.Vector3(0,10,0), new THREE.Vector3(0,-10,0));
var planoref = new THREE.Plane(new THREE.Vector3(0,1,0), -5);
alert( planoref.intersectLine(line).y);
Related
I'm working on an app where I visualize ATV trails in a 3d perspective (NAIP imagery draped over elevation data). I am using three.js for the rendering engine.
In the above image, the white line you see is just a THREE.Line instance, where I convert a trails gps coordinates into threejs coordinates. I'd like to add more of 3d perspective to this line. I tried implementing a THREE.TubeGeometry where the path was a THREE.CatmullRomCurve3 using the same Vector3 points as how I built the line you see in the image above. That did not produce a desirable result...
From the many, many THREE examples I have looked at, I really think an extruded geometry would achieve the look I am after... But I cant for the life of me figure out how to extrude a geometry for the line. Any suggestions/thoughts?
UPDATE 1:
Here is my desired look (same trail - no imagery). This image was produced in QGIS using the Q2Threejs plugin
UPDATE 2: Here is a code of how I have attempted to create a tubegeometry. Maybe I am messing something up in there...
// trailVectors are an array of Vector3 - same as ones used to create line
var trailCurve = new THREE.CatmullRomCurve3(trailVectors);
var tubeGeometry = new THREE.TubeGeometry(trailCurve,80,1,15,false);
var material = new THREE.MeshBasicMaterial({color:0x00ff00});
var tubeMesh = new THREE.Mesh(tubeGeometry,material);
var wireframeMaterial = new THREE.LineBasicMaterial({color:0xffffff,lineWidth:2});
var wireframe = new THREE.Mesh(tubeGeometry,wireframeMaterial);
tubeMesh.add(wireframe);
scene.add(tubeMesh);
UPDATE 3
THREE.TubeGeometry(trailCurve,80,4,2,false) per mzartman request
I think that you should be able to achieve what you want with a TubeGeometry. I think the big thing is that your example (from the picture shown) has more than 2 radius segments. That gives it the tubular shape and makes it look sort of like a blob. If you set the radial segment count to 2 (as it's shown below) then I think it would look a lot better.
tubeGeometry = new THREE.TubeBufferGeometry(
[YOUR_PATH_HERE],
params.extrusionSegments, // <--- Edit this for higher resolution on the spline
3, // <--- This defines the height
2, // <--- This 2 keeps 2D (i.e. not a tube!!!!)
true );
var mesh = new THREE.Mesh( geometry, material );
var wireframe = new THREE.Mesh( geometry, wireframeMaterial );
mesh.add( wireframe );
scene.add( mesh );
Update:
I think that you might do better with a material that shows some shadow like the MeshPhong. Also, to do the wireframe you want to add it as an option in the material initialization. Give it a show with the following:
var tubeGeometry = new THREE.TubeGeometry(curve,80,1,2,false);
var material = new THREE.MeshPhongMaterial({color:0x00ff00, wireframe: true});
var tubeMesh = new THREE.Mesh(tubeGeometry,material);
scene.add(tubeMesh);
I'm very new to both three.js & to js in general.
1st I select a polyHedron geometry with a dat.gui checkbox
which renders say a tetrahedron. these selections work.
I also have a dat.gui checkbox to either phongfill or wireframe render.
I initially wanted just a wireframe type mesh but not with all of the internal triangles. I found the edgesgeometry() function which draws pretty much what I want(hard edges only). there is however a known issue with linewidth not working in windows anymore. all lines drawn as strokeweight/width 1.
I'd like to use tubeGeometry() to draw tubes of whatever radius as opposed to 1weight lines. I know I'll have to draw something such as a sphere at/over the connection vertices for it to not look ridiculous.
geo = new THREE.TetrahedronBufferGeometry(controls0.Radius,controls0.Detail);
...
egeo = new THREE.EdgesGeometry( geo );
lmat = new THREE.LineBasicMaterial({ color: 0x0099ff, linewidth: 4 });
ph = new THREE.LineSegments( egeo, lmat );
scene.add(ph);
....
playing around in the console I found some geometry/bufferGeomery arrays that are likely the vertices/indices of my selected X-hedron as their sizes change with type(tetra/icosa etc) selection & detail increase/decrease:
//p = dome.geometry.attributes.uv.array;
p = egeo.attributes.position.array
//p = geo.attributes.uv.array
...
var path = new THREE.Curve();
path.getPoint = function (t) {
// trace the arc as t ranges from 0 to 1
var segment = (0 - Math.PI*2) *t;
return new THREE.Vector3( Math.cos(segment), Math.sin(segment), 0);
};
var geomet = new THREE.TubeBufferGeometry( path, 10, 0.2, 12, false );
var mesh = new THREE.Mesh( geomet, mat );
scene.add( mesh );
from above the tubeGeometry() draws fine separately as well but with the "path" made by that curve example. How can I use the vertices from my tetrahedron for example to create that "path" to pass to tubegeometry() ?
maybe a function that creates "segment vectors" from the vertices ?
I think it needs other properties of curve/path as well ?
I'm quite stuck at this point.
ANY Help, suggestions or examples would be greatly appreciated !
thanks.
You can try to create a TubeGeometry for each edge. Generate a LineCurve3 as the input path. Use the vertices of the edge as the start and end vector for the line.
Consider to use something like "triangulated lines" as an alternative in order to visualize the wireframe of a mesh with a linewidth greater than 1. With the next release of three.js(R91) there are new line primitives for this. Demo:
https://rawgit.com/mrdoob/three.js/dev/examples/webgl_lines_fat.html
This approach is much more performant than drawing a bunch of meshes with a TubeGeometry.
I have a simple rectangular wall and I like to place multiple window holes on it. It always works great for the first hole, but as soon as I add additional holes the polygon becomes messed up. See the images below to see what I'm talking about.
How can I draw holes properly in Three.js?
The right hole is not drawn properly.
After increasing the height of the right hole the entire wall mesh becomes halfcut.
Here is a sample code that causes above problem:
var shape = new THREE.Shape();
shape.moveTo(0, 0);
shape.lineTo(1, 0);
shape.lineTo(1, 1);
shape.lineTo(0, 1);
var windowHole = new THREE.Path();
windowHole.moveTo(0.14999999888241292, 0.7758620689655171)
windowHole.lineTo(0.4999999962747097, 0.7758620689655171)
windowHole.lineTo(0.4999999962747097, 0.3448275862068965)
windowHole.lineTo(0.14999999888241292, 0.3448275862068965)
shape.holes.push(windowHole);
windowHole = new THREE.Path();
windowHole.moveTo(0.5999999955296517, 0.7758620689655171)
windowHole.lineTo(0.7499999944120646, 0.7758620689655171)
windowHole.lineTo(0.7499999944120646, 0.6034482758620688)
windowHole.lineTo(0.5999999955296517, 0.6034482758620688)
shape.holes.push(windowHole);
var mesh = new THREE.Mesh(new THREE.ShapeGeometry(shape), this.material);
root.add(mesh);
The above code results in a warning:
Warning, unable to triangulate polygon!
at public_html/libs/three.js:27785
It turned out that this was a bug that is now fixed in version 66dev.
The bug was reported and discussed here:
https://github.com/mrdoob/three.js/issues/3386
The fixed version that I'm using now is developer built version 66dev committed at Jan 27th, 2014 here:
https://github.com/mrdoob/three.js/tree/dev/build
I assume this fix will be merged with the main three.js soon, but until then you can use the link above.
Some code might help. if possible link your code in jsfiddle...
just you need to change the order of the path creation... refer the link... http://jsfiddle.net/ebeit303/BuNb2/
var shape = new THREE.Shape();
shape.moveTo(-5, -5);
shape.lineTo(-5, 5);
shape.lineTo(5, 5);
shape.lineTo(5, -5);
shape.lineTo(-5, -5);
var windowHole = new THREE.Path();
windowHole.moveTo(-2,-2);
windowHole.lineTo(0,-2);
windowHole.lineTo(0,0);
windowHole.lineTo(-2,0);
windowHole.lineTo(-2,-2);
shape.holes.push(windowHole);
windowHole1 = new THREE.Path();
windowHole1.moveTo(3,3);
windowHole1.lineTo(4,3);
windowHole1.lineTo(4,4);
windowHole1.lineTo(3,4);
windowHole1.lineTo(3,3);
shape.holes.push(windowHole1);
var geometry = new THREE.ShapeGeometry( shape );
var material = new THREE.MeshBasicMaterial({color:0xffccff, side:2, overdraw:true} );
var mesh = new THREE.Mesh(geometry, material );
group.add(mesh);
Have a look on http://learningthreejs.com/data/constructive-solid-geometry-with-csg-js/. Whatever your codes are it will help you in doing it better. Substraction, addition, union, intersection everything is possible.
I have some code similar to the following...
this.texture = new THREE.ImageUtils.loadTexture( 'spritesheet.png' );
this.material = new THREE.MeshBasicMaterial( { map: this.texture, side:THREE.DoubleSide } );
this.geometry = new THREE.PlaneGeometry(32, 32, 1, 1);
this.sprite = new THREE.Mesh( this.geometry, this.material );
game.scene.add( this.sprite );
I've also tried along the lines of...
this.material = new THREE.SpriteMaterial( {
map: image,
useScreenCoordinates: true,
alignment: THREE.SpriteAlignment.center
} );
this.sprite = new THREE.Sprite( this.material );
These display the full spritesheet (sort of), as I would expect without further settings.
How do I align the sprite so it only displays say 32x32px starting at offset 50,60 for example ? The three.js documentation doesn't seem have much information, and the examples I've seen tend to use one image per sprite (which may be preferable, or only way possible ?)
Edit: I've spotted a material uvOffset and uvScale that I suspect is related to alignment in a Sprite object if anyone knows how these work. Will dig further.
Well, there is a "uvOffset" and "uvScale" parameter in spriteMaterial , i think you could use those but I cannot present any source code to you.
What you can of course do is using PlaneGeometry and calculate UV Coordinates for the 2 triangles (the plane). For example top-left is your offset and bottom right is calculated from a given offset and size (32x32) but using the whole image size in pixels to get the UV coordinates between 0 and 1
for example topleft is (50/imageSize, 60/imagesize) and bottom right is ( (50+32)/imgSize, (60+32)/imgSize). I think this should work, although i am not quite sure if you would get the result you want as OpenGL treats images "up side down". But you can try and go on from here. Hope this helps.
I have this object I'm loading with THREE.objLoader and then create a mesh with it like so:
mesh = new THREE.SceneUtils.createMultiMaterialObject(
geometry,
[
new THREE.MeshBasicMaterial({color: 0xFEC1EA}),
new THREE.MeshBasicMaterial({
color: 0x999999,
wireframe: true,
transparent: true,
opacity: 0.85
})
]
);
In my scene I then add a DirectionalLight, it works and I can see my object, however it's like the DirectionalLight was an ambient one. No face is getting darker or lighter as it should be.
The object is filled with the color, but no lighting is applied to it.
If someone can help me with that it would be much appreciated :)
What could I be missing ?
Jsfiddle here: http://jsfiddle.net/5hcDs/
Ok folks, thanks to Maël Nison and mr doob I was able to understand the few things I was missing, being the total 3d noob that I am... I believe people starting to get into the 3d may find useful a little recap:
Basic 3d concepts
A 3d Face is made of some points (Vertex), and a vector called a normal, indicating the direction of the face (which side is the front and which one is the backside).
Not having normals can be really bad, because lighting is applied on the frontside only by default. Hence the black model when trying to apply a LambertMaterial or PhongMaterial.
An OBJ file is a way to describe 3D information. Want more info on this? Read this wikipedia article (en). Also, the french page provides a cube example which can be useful for testing.
Three.js tips and tricks
When normals are not present, the lighting can't be applied, hence the black model render. Three.js can actually compute vertex and face normals with geometry.computeVertexNormals() and/or geometry.computeFaceNormals() depending on what's missing
When you do so, there's a chance Three.js' normal calculation will be wrong and your normals will be flipped, to fix this you can simply loop through your geometry's faces array like so:
/* Compute normals */
geometry.computeFaceNormals();
geometry.computeVertexNormals();
/* Next 3 lines seems not to be mandatory */
mesh.geometry.dynamic = true
mesh.geometry.__dirtyVertices = true;
mesh.geometry.__dirtyNormals = true;
mesh.flipSided = true;
mesh.doubleSided = true;
/* Flip normals*/
for(var i = 0; i<mesh.geometry.faces.length; i++) {
mesh.geometry.faces[i].normal.x = -1*mesh.geometry.faces[i].normal.x;
mesh.geometry.faces[i].normal.y = -1*mesh.geometry.faces[i].normal.y;
mesh.geometry.faces[i].normal.z = -1*mesh.geometry.faces[i].normal.z;
}
You have to use a MeshPhongMaterial. MeshBasicMaterial does not take light in account when computing fragment color.
However, when using a MeshPhongMaterial, your mesh becomes black. I've never used the OBJ loader, but are you sure your model normales are right ?
Btw : you probably want to use a PointLight instead. And its position should probably be set to the camera position (light.position = camera.position should do the trick, as it will allow the light to be moved when the camera position will be edited by the Controls).