I have a single mesh game object that is essentially a long line that curves and slopes up/down. What I'm trying to do is generate some text along this line at a specified distance interval. Let's say every 100 units along the line some text should appear. If it was a straight line it would be easy, but the curves and slopes are throwing me off.
I retrieved the vertices that created this mesh by doing:
model.GetComponent<MeshFilter>().mesh.vertices
I then transform them to world-space by looping over them and doing:
meshFilter.gameObject.transform.TransformPoint(vertices[i])
Now, these vertices are NOT evenly spaced. For slopes and curves, there are a lot of vertices. For the straighter parts, there are less. But these straight parts still vary slightly (usually by ~.10 of the Y value). Originally I was looping through and keeping track of the distance to find the vertices closest to the interval, but that was when I thought they were evenly spaced.
Here's part of the model:
I colored all the vertices black here to show how condensed they are at curves/slopes vs ~straight parts:
Here's the inspector for the model just incase:
Do you use a static single mesh?
In your solution, I think the problem is vertices. you have to find vertices along your line and ignore the vertical group of them and its too difficult.
If your mesh may be changed by player, I suggest you to use Trail Render Component, get its vertices and solve a simple Knapsack problem to put your characters (suggest you use TextmeshPro)
Related
I have a problem where we have a grid of points and I'd like to fit a "deformed grid which would best fit the set of points.
The MatLab data can be found at:
https://drive.google.com/file/d/14fKKEC5BKGDOjzWupWFSmythqUrRXae4/view?usp=sharing
You will see that cenX and cenY are the x and y coordinates of these centroids.
Like on this image. To note is that there are points missing, and there are a few extra points. Moreover, You can see some lines are not one single line from left to right, however, we could safely assume that the fitting a line somewhat horizontally (+-5degrees) would properly link the points into a somewhat deformed grid.
The vertical lines are trivial because that is how we generated these dots. We can find the number of lines required through a mode of the count of points on each of the columns of the grid.
I'd like to be able to ensure that a point is only part of one line, as this is a grid.
I am trying to pack same-radi circles on a sphere using matlab. I have figured out how to pack circles and spheres in a box or a cube but just can't figure out where to start when packing it on the surface of a sphere. I would love any hints or ideas in doing this.
Wish you all the best of luck
This is a really hard problem, not sure if there exists a generic solution.
To obtain perfectly regular distribution of circles, take any regular polyhedron, and put a circle at each vertex. The largest regular polyhedron, the dodecahedron has 20 vertices, so you would be able to fit 20 circles on a sphere with this method. If you are willing to have a tiling that is not perfectly regular, you can use shapes such as that of a buckyball (same as soccer ball).
Other ways to distribute points evenly around a sphere have been proposed.
A friend of mine proposed a way that allowed him to easily index each point. It was based on the icosahedron (dual of the dodecahedron, it has 20 faces), and tiled each triangular face. See his paper for more details.
That paper has references to some other methods known at that time. I think the most useful one would be the one where the sphere is cut vertically into slices of equal width (the surface of the sphere section has equal height, the cuts themselves are not spaced evenly), and each section is then a strip that can be tiled by circles evenly. This leads to one circle on the top and one on the bottom, and in between rows of circles. The distribution is not even, and the spacing depends on the ratio of the circle size and sphere size.
I have an .obj file representing a 3D object.
I need to extract from this 3D object the contour that is obtained by intersection with a plane. So for example, I have an object representing a cylinder oriented with vertical axis, then I want to extract a circle contour when the intersecting plane is horizontal or a rectangular contour when the intersection plane is vertical. Any suggestion about how to do it?
Since I didn't know how to visualise this obj file, I have converted to a patch with the following code (some function taken from loadawobj from Matlab file exchange).
modelname='file.obj';
S=loadawobj(modelname);
mtl=loadawmtl(['obj/' S.mtllib]);
p3=patch('Vertices',S.v','Faces',S.f3');
for ii=1:length(S.umat3)
mtlnum=S.umat3(ii);
fvcd3(ii,:)=mtl(1).Kd';
end
p3.FaceVertexCData=fvcd3;
p3.FaceColor='flat';
But I don't necessarily need to extract the contour from the resulting patch if this is too complex to accomplish. If there is an easier procedure starting from the obj file, it's also fine and acceptable. Thank you!
That's the way I solved the problem, after collecting information all around the web. I couldn't find anything ready on line so I had to implement an algorithm on my own. The basic idea is very simple but there are many steps required. I start from two info: one array containing the coordinates of the cloud point and another array containing a bunch of tuples about how the 3 vertex are connected to form a triangle.
First of all you need to find a representation of the plane you want to use for your cutting. That means you just use one point and the normal to the plane to represent it. That plane is required in order to identify the cutting point on the structure.
Second step is to identify the triangles on the plane. In few words you just need to scroll over all the triangles of the structure and find those having one corner above the cutting plane and another corner below the cutting plane. Also don't forget to account for the condition where one corner is on the plane or two are on the plane. All the other triangles are not needed, since they are totally above or below the cutting plane.
Now you have a subset of all your triangles. You need to extract points of the contour. So for each triangle you have 3 vertex: in general case you can imagine that one vertex is above the plane and the other two are below. Then you have two lines cutting the plane. You can extract two point by simply intersecting these lines with the cutting plane.
By repeating this operation you get a series of points on 2D space. But they have no order and if you plot them as a continuous plot, you get lines jumping up and down since the points you have extracted are randomly located in the array. So, it's required to order them in a proper way. The method I used is the very simple: start from one point and connect to the closest one. There are some bad situations where that doesn't work but you can probably avoid it by adding some more rules on the algorithm.
I want an approach and method to separate the connected lines. Here is my image
and here is the result I would like
How do I solve that problem? Thank you in advance!
Sincerely
The watershed would be a problem as you have shown it produces multiple segmentations of the original line. Originally the watershed works for grains due to their convex shapes, while here in the case of lines there is no global convex shape to cause a good fragmentation, it would be good to use the watershed with some constraints.
It would be good to try solving a simpler version of the problem. Imagine that there are only horizontal and vertical lines possible. So in this case it would mean separating the horizontal long lines by cutting the short vertical lines (length measured by projecting on the x-y gradient). The basic hint is to use the gradient/slope of these lines to help decide where to cut - orthogonal line. In the more general case the problem requires a measure of local curvature or geodesic distance.
A simpler solution(in edit) is just removing the junction points in the skeleton you have.
This would cause some of your lines which are connected horizontally to be segmented but i guess this can be fixed with some end point filtering. A simple try here:
J = imread('input.png');
B = bwmorph(J,'branchpoints');
L = bwlabel((J>0).*(~B),8); %removing the branch points from the skeleton
Label = label2rgb(bwlabel((J>0).*(~B),8),'jet',[0 0 0]);
Final labeled line components. This requires further end point prefiltering, direction based filtering.
The parts of the contour that should be separated are basically the sections that are not in the same direction as most of the rest of the contour.
I can only give you a basic way to do this without specific code or functions and I doubt it is the most efficient, but since there are not too many answers here...also this is using the knowledge of the problem and the solution...
Find the connected contour with all its branches as a set of pixel coordinates (which represent the line as a single pixel wide contour)
Convert the contour list to a set of angles between each adjacent pixel coordinate
Optional: Filter out the high frequency components with an averaging filter
Histogram the angles to find the angle most of the contour lines lay on (call it the common angle)
Search the contour looking for sections that go from +/-common angle (tolerance of +/-30 degrees) to the negative of that (-/+ common angle with similar tolerance).
For each section delete the pixels associated with angles between the two thresholds above (i.e. common angle + 30 deg to -common angle - 30 degrees.
Repeat for each connected contour
Hope this helps some
I have an array of CGPoints (basic struct with two floats: x and y). I want to use OpenGL ES to draw a textured curve using these points. I can do this fine with just two points, but it gets harder when I need to make a line from several points.
Currently I draw a line horizontally, calculate its angle from the points given, and then rotate it. I don't think doing this for all lines in a curve is a good idea. There's probably a faster way.
I'm thinking that I can "enlarge" or "constrict" all the points at once to make a curve with some sort of width.
I'm not positive what you want to accomplish, but consider this:
Based on a ordered list of points, you can draw a polyline using those points. If you want to have a polyline with a 2D texture on it, you can draw a series of quadrilaterals (using two triangles each, of course). You can generate these quadrilaterals using an idea similar to catmul-rom spline generation.
Consider a series of points p[i-1], p[i], p[i+1]. Now, for each i, you can find two points each an epsilon distance away from p[i] along the line perpendicular to the line connecting p[i-1] and p[i+1]. You can determine the two points generated for the endpoints in various ways, like using the perpendicular to the line from p[0] to p[1].
I'm not sure if this will be faster than your method, but you should be caching the results. If you are planning on doing this every frame, another type of solution to your problem may be needed.