I think i have a difficult problem right here..
I want to able to get the surfaces of f.e. the orange object in this three.js example https://threejs.org/examples/?q=stl#webgl_loader_stl
i want to click with the mouse, find the correct surface, which should then be highlighted, so i make sure this was the surface i want.
(i already implemented raycaster successfully, so thats not an issue)
The intersectObject method returns an array of intersections, each of which has face property. The face contains vertex indices.
For STL files containing multiple solids, each solid is assigned to a different group, and the groups are available in the geometry object that is returned from STLLoader. Each group is defined by a range of vertex indices.
So, I think you can correlate the vertex indices returned from the raycaster with the vertex indices in the geometry groups.
Related
So, I'm using a boolean operator to get the intersection of a bunch of pieces and a wall. Most pieces work fine but occasionally the intersection isn't perfect and you get these vertices that aren't connected to the rest of the mesh and this results in the mesh collider being incorrect, as seen in this picture.
My question is whether there is a way to detect these 'island' or 'lone' vertices.
I can provide additional images, code, or such if needed.
Thanks for any help! Ps. first question here so please be patient with me :)
In the end, I kind of solved it by finding all connected vertices starting from a single vertex.
I started by picking the first triangle and adding it's vertices to a list of connected vertices. Then I go through the list of triangles comparing the position of their vertices to the list of connected vertices. If the triangle has a vertex with a position corresponding to a position in the list of connected vertices I add the entire triangle to the list. That's one iteration and I repeat this until all connected triangles are already in the list. If the connected triangle list is more than half of all triangles then I remove all other triangles, otherwise, I remove the current list of connected triangles. After that, I clear the vertices that aren't in a triangle like Leo Bartkus suggested.
It's extremely slow and it assumes there are only 2 separate islands or that you started on the biggest island, but it worked most of the time and was more for learning purposes anyways.
Thank's for the help!
I am currently developing an asteroid mining/exploration game with fully deformable, smooth voxel terrain using marching cubes in Unity 3D. I want to implement an "element ID" system that is kind of similar to Minecraft's, as in each type of material has a unique integer ID. This is simple enough to generate, but right now I am trying to figure out a way to render it, so that each individual face represents the element its voxel is assigned to. I am currently using a triplanar shader with a texture array, and I have gotten it set up to work with pre-set texture IDs. However, I need to be able to pass in the element IDs into this shader for the entire asteroid, and this is where my limited shader knowledge runs out. So, I have two main questions:
How do I get data from a 3D array in an active script to my shader, or otherwise how can I sample points from this array?
Is there a better/more efficient way to do this? I thought about creating an array with only the surface vertices and their corresponding ID, but then I would have trouble sampling them correctly. I also thought about possibly bundling an extra variable in with the vertices themselves, but I don't know if this is even possible. I appreciate any ideas, thanks.
I am trying to create an advanced shader for an AR application in Unity. Therefore I need all vertices and their neighbors from my gameobject (within a C# script). Getting the vertices is not the problem, but how do I get their neighbors(maybe with an indexbuffer)?
I am not new to shaders, but to shaders within Unity.
After I got the neighbors I would like to pass them from a C# script to a function within a shader file. I guess that should be possible in Unity, is it not?
The easiest way I can think of is by searching the triangle index. The pattern is always the same, always 3 indices define a vertex. since you know the index of your vertex, you can just search the triangle array and return the other two of any triangle, which will give you all vertices within the range of the desired one.
Dynamically creating a mesh with a hole in it from two lists of vertices
I am currently attempting to dynamically create a mesh (2D) with a hole in it. I have a list of Vector3 vertices for both the outline and the hole's outline.
My question:
How would I go about merging these two lists of vertices into a single mesh?
More detail: I have two meshes that overlap, and I'm trying to do a boolean difference between the two, to create a new mesh that will eventually replace the bigger one, to get rid of clipping. Example
Using the Clipper-Library (see http://www.angusj.com/delphi/clipper.php) is of no use, because it returns the same two sets of vertices that I set as input.
I'm guessing I need to somehow fix the triangles for the mesh to create triangles between the outer and inner vertices? (The meshes can be any shape/size, so finding out which vertexes to combine into triangles is no easy task).
Can anybody tell me how I would create a single mesh out of the two vertex-loops?
If you need a generic boolean algorithm this is a very hard problem, for example 3D Studio Max has two seperate boolean mesh creators, each failing at different sets of objects.
If you only need to subtract rectangular, aligned shapes, which do not touch, its simpler. For your specific case you can just join the list of vertexes, and fill new list of triangles - you'll need two tris per quad, so thats eight triangles stretched across eight verices.
It gets a bit harder if they start to touch, as you need to find intersection points and basically re-triangulate the outline.
I have 3 OpenGL objects which are shown at the same time. If the user touches any one of them, then that particular OpenGL object alone should display in screen.
Just use gluUnProject to convert your touch point to a point on your near clipping plane and a point on your far clipping plane. Use the ray between those two points in a ray-triangle intersection algorithm. Figure out which triangle was closest, and whatever object that triangle is part of is your object. Another approach is to give each object a unique ID color. Then, whenever the user touches the screen, render using your unique ID colors with no lighting, but don't present the render buffer. Now you can just check the color of the pixel where the user touched and compare it against your list of object color ID's. Quick and easy, and it supports up to 16,581,375 unique objects.
You would have to parse every object of your scene and check the possible collision of each one of them with the ray you computed thanks to gluUnProject.
Depending on whether you want to select a face or an object, you could test the collision of the ray with bounding volumes (e.g. bounding box) of your objects for efficiency purposes.