I have a 3dpolyline and arc (3D). I 'm wondering if I can join 3dpolyline with 3d arc to get 3dpolyline. While seraching on this topic i found that I need first a routine that converts arc to 3dpolyline and then join two 3dpolylines. Does some one knows some link.?
A 3D polyline is a connected sequence of straight line segments created as a single object. 3D polylines can be non-coplanar; however, they cannot include arc segments.
http://docs.autodesk.com/ACD/2010/ENU/AutoCAD%202010%20User%20Documentation/index.html?url=WS73099cc142f48755-471cc4bd11960d8a16c-1c8.htm,topicNumber=d0e290136
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I have made the shape of Hello Kitty (I started from a cube, merged all the vertices at the center and then I add one by one the vertices with CTRL+RightMouseButton and then I used fill to obtain the face) but when I go to UVediting tab I see only one point. I don't know what's wrong
You'll need to unwrap your mesh using the U hotkey, and you'll likely want to learn about "pelt" mapping (aka UV unwrapping using seams)
I am trying to fit known well-defined shapes (eg boxes, cylinders; with configurable positions, rotations and dimensions) to a set of points with normals generated from sampling a 3D mesh. My current method is to define a custom fit function for each shape and pass it to a third-party optimisation function:
fitness = get_fitness(shape_parameters, points)
best_parameters = external.optimise(get_fitness, initial_parameters, points)
(for reference, I'm currently using Python 3 and scipy.optimize.minimize with bounds, but language is irrelevant).
This fitness function for a rectangle would look something like
def get_fitness(parameters, points):
side_fitnesses = []
for side in [top, right, bottom, left, back, front]:
dists = get_side_distances(parameters, points, side)
ndevs = get_side_normal_deviations(parameters, points, side)
side_fitnesses.append(combine_dists_and_ndevs(dists, ndevs))
fitnesses = choose_best_side_for_each_point(side_fitnesses)
return mean(fitnesses)
However this means I have to determine outliers (with/without caching), and I can only fit one shape at a time.
For example (in 2D), for these points (with normals), I'd like the following result:
Notice that there are multiple shapes returned, and outliers are ignored. In general, there can be many, one or zero shapes in the input data. Post-processing can remove invalid (eg too small) results.
Note: my real problem is in 3D. I have segments of a 3D mesh representation of real-world objects, which means I have more information than just points/normals (such as face areas and connectivity) which are in the example above.
Further reading:
Not well-defined shape-fitting
Highly technical n-dimensional fitting
Primitive shape-fitting thesis
Unanswered SO question on something similar
PS: I'm not sure if StackOverflow is the best StackExchange site for this question
well so you will have to handle meshes with volume then. That changes things a lot ...
segmentate objects
be selecting all faces enclosing its inside ... So its similar to this:
Finding holes in 2d point sets?
so simply find a point inside yet unused mesh ... and "fill" the volume until you hit all the faces it is composed of. Select those faces as belonging to new object. and set them as used... beware touching objects may lead to usage of faces twice or more ...
You can do this also on vector math/space so just test if line from some inside point to a face is hitting any other face ... if no you found your surface face ... similar to Hit test
process object (optional)
you can further segmentate the object mesh into "planar" objects that it is composed of by grouping faces belonging to the same plane ... or inside enclosing edge/contour ... then detect what they are
triangle
rectangle
polygon
disc
from count and type of faces you can detect basic objects like:
cone = 1 disc + 1 curved surface with singular edge point parallel to disc center
box/cube = 6 rectangles/squares
cylinder = 2 discs + 1 curved surface with center axis going through discs centers
compute basic geometric properties of individual objects (optional)
like BBOX or OBB, surface, volume, geom. center, mass center, ...
Now just decide what type of object it is. For example ratio between surface area and volume can hint sphere or ellipsoid, if OBB matches sides it hints box, if geom and mass centers are the same it hints symmetrical object ...
pass the mesh to possible object type fitting function
so based on bullets #2,#3 you have an idea which object could be which shapes so just confirm it with your fitting function ...
to ease up this process you can use properties from #3 for example of this see similar:
ellipse matching
so you can come up with similar techniques for basic 3D shapes...
I want to create 3 concentric arcs with line and labels with some HTML in the center.
One of the third arc overlaps the second arc. I want to add polylines with the labels to make it more descriptive.
below is the work done so far
I am attempting to render a flat, dynamically created heatmap on top of a 3D model that is loaded from an OBJ (or STL).
I am currently loading and rendering an OBJ with Three.js. I have vector3 points that I am currently drawing as simple red cubes (image below). These data points are all raycasted to my OBJs mesh and are lying on the surface. The vector3 points are loaded from an external data source and will change depending on what data is being viewed/collected.
I would like to render my vector3 point data into a heatmap on the surface of my OBJ. Here are some examples illustrating the type of visual effects I am trying to achieve:
I feel like vertex coloring is the method of achieving this, but my issue is that my OBJ model does not have enough tessellation to do this. As you can see many red dots fall on each face. I am struggling to find a way to draw over my object's mesh with colors exactly where my red point data is. I was assuming I would need to convert my random vector3 points into a mesh, but cannot find a method to do so.
I've looked at the possibility of generating a texture, but 1) I do not have a UV map for my OBJs and do not see a way to programmatically generate them and 2) I am a bit lost on how I would correlate vector3 point data to UV points.
I've looked at using shaders, but my vector3 point data appears to be too large for using a shader (could be hundreds of thousands of points). I also feel it is not the right approach to render the heatmap every frame and would rather only render it once on load.
I've looked into isosurfaces with point clouds and the marching cubes algorithm, but I didn't think this was the right direction since only my data is a bit like a point cloud, and I am unsure as to how I would keep this smooth along the surface of my OBJ mesh.
Although I would prefer to keep everything in JavaScript for viewing in the browser, I am open to doing server side processing in any language/program with REST so long as it can be automated without human intervention, and pushed back to the browser for rendering.
Any suggestions or guidance is appreciated.
I'm only guessing but it seems like first you need to have UV coordinates that map every triangle to a texture. Rather than do this by hand I'd suggest using a modeling package. Most modeling packages have some way of automatically and uniformly mapping every triangle to a texture. For example in Blender
Next to put the heatmap in the texture by computing which triangles are affected by each dot (your raycasting), looking up their texture coordinates, projecting that dot into texture space and then putting the colors in that part of the texture. I'm only guessing that you need to not just do exact points but probably need to consider adjacent triangles since some heat info that hits near the edge of a triangle needs to bleed over into the adjacent triangle but that adjacent triangle might be using a completely different part of the texture.
So I'd like to create some lines that can be modified from points that are connecting them.
An example of initial state
First one has been moved down, second one up and third one right and down.
On the implementation side I currently have two meshes. First one is stretched out so that it would cover the distance from its starting point to the next point and second one marks the starting point.
var meshLine = new THREE.Mesh(boxGeometry, material);
meshLine.position.set(x,y,z);
meshLine.scale(1,1,distancetonextpoint);
var meshPoint = new THREE.Mesh(sphereGeometry, material);
meshPoint.position.set(x,y,z);
meshPoint.scale(2,2,2);
What I want from it is that when the user drags the circular point other lines would stretch or change their position accordingly to the one being dragged.
Is there some more reasonable solution for this as I feel mine is not quite good and clean. I'd have to do quite heavy lifting to get the movement done.
I've also looked at this example which looks visually very nice but could not integrate it to my system.
You mean you need to edit the object's geometry by dragging their vertices (here a line).
Objects'vertices can't be dragged theirselves, so you need to loop through the geometry and create little spheres at each vertex position ;
You set a raycaster to pick those spheres, as in the examples ;
Your screen is 2D so to drag objects in 3D you need a surface perpendicular to the screen, that intersects the sphere position. For this you set an invisible plane at the vertex position and make it look at the camera ;
Once you can correctly drag the spheres, you tell the corresponding vertices on the object (your lines) they must keep the same position as their spheres ;
End with geometry.verticesNeedUpdate=true.
And you have your new geometry
For code details on picking objects look at the official picking objects'example draggable cubes
This example shows how to use it for editing objects
Comment if you need more explanations