I'm working in Unity and thus coding in C#, but any idea or a place to start is welcome.
I don't really know how to describe my problem, and if there is a 'simple' solution for it, but I'll try.
I have an object (probably going to limit myself to simple shapes) that casts 2 shadows.
I'd like to generate a mesh that is the shape of that shadow.
As you can see on the image below, I drew the desired meshes in green.
desired meshes drawn in green
I've messed around with altering the vertices of my initial mesh, and in some specific cases (objects with no rotation) found a solution, but I haven't found one that's works well enough.
Does anyone have an idea that could work?
Thanks in advance,
Bart
I took the time to create a project that does exactly what you said:
Preview it here
The Method
Using raycasts I calculated the projected vertices of a specific object from a light source. The method may seem inefficient but as long as the specified mesh has a low vert count everything should be fine.
Then by taking the average of projected vertices I calculated the position of the projected cube.
Vector3 averagePosition = new Vector3(verticies.Average(vector => vector.x),
verticies.Average(vector => vector.y),
verticies.Average(vector => vector.z));
And by taking the range each of the projected vertex position components (x,y,z) I calculated the scale of the cube.Vector3 averageScale = new Vector3(verticies.Max(vector => vector.x) - verticies.Min(vector => vector.x), verticies.Max(vector => vector.y) - verticies.Min(vector => vector.y), normalScale);
Note: I am not generating a whole new mesh. I am just manipulating the transform of a pre-made cube with a script attached.
Downside is that this method is only limited to one axis so far. Can be fixed.
Download the project from Github
GitHub link: https://github.com/MyIsaak/Shadow-Mesh/tree/master
Would be great if you could commit any improvements you make to help the community. You are free to use this project for commercial and non commercial use.
Related
I have a simple teapot mesh and a point cache animation that matches that mesh.
Everything is exported from 3DS Max.
When I try to load it into unity, and load the point cache into the mesh, there is a vertices mismatch.
Upon further debugging I saw that indeed unity adds more vertices than there is in the original mesh, which means I cannot match the point cache animation to the mesh now.
I saw on the RecalculateNormals page and it say's:
Imported Meshes sometimes don't share all vertices. For example, a
vertex at a UV seam is split into two vertices, so the
RecalculateNormals function creates normals that are not smooth at the
UV seam.
So, unity adds more vertices to the original mesh.
What can I do to fix that so my point cache match the mesh? there is no documentation how unity does that, nor is there a way to turn it off.
Note: I tried changing the import setting (and export setting on max) like:
Mesh compression -> Nothing
Optimize mesh -> Nothing
Keep Quads -> ON
Weld Vertices -> OFF
Smoothness Source -> None
And more...
Everything is set and tested separately & together. Nothing seem to lower the vertex count.
Vertex duplication is generally unavoidable.
Turning off split per-vertex normals in the fbx exporter settings in max is supposed to solve this problem, but it will remove all seams from your model.
Personally, I would work around this in maxscript by exporting the entire mesh as fbx at each $t instead of writing out the point cache.
I found this tool, the Oasis Mesh Editor, that can Split Vertices and Merge Vertices back together, https://assetstore.unity.com/packages/slug/166155
The Merge Verts tool also has a Max Tolerance setting so that only verts that are closer than this distance will be merged.
Hope this helps anyone looking =)
I am beating my head a little bit here for a while but I still could bot find a way to set up a matrix that projects my Unity game in a Tibianeske like manner:
Reading on tutorials on internet I could figure out how a normal orthographic perspective works, but tibia's one is kind of odd.
Digging over webs I found in here a guy (Clint Bellanger) who describes really well how to get the same perspective in blender's render according to him:
Start with a scene in 45 degree isometric. Video game style, where
the camera angle is Blender (60,0,45).
In Blender if you look at Buttons Window -> Scene -> Render Buttons ->
Format, you can set the render aspect ratio. Set AspY to half of
AspX. This is the same as taking regular rendered output and scaling
X by 50%. If you rendered a cube, the top of the cube will be a
perfect square (though at a 45 degree angle).
We can then use Blender nodes to rotate the result 45 degrees. The
output:
Note this started as a cube, so there's a lot of "vertical"
distortion. So you might have to scale meshes to 50% Z before using
this method. Also notice the Edge seems to be applied after the
Aspect, so the edge isn't distorted.
Blend file: http://clintbellanger.net/images/temp/UltimaVII.blend (I'm
a Nodes noob so there might be a smarter setup).
For kicks, here is that tower again. I pulled it into the above
workflow scene and scaled Z by 50%. Click "Re-render this layer" on
the first node to create the composite.
On his method, he used stuff like rescaling the render and changing the scale of models, Im convinced I could get along just with the 4x4matrix in unity(or in any other 3d environment really).
Hope someone more experienced with perks of 3D maths could help me to figure it out. Thank you! =D
What you ask for is a simple parallel projection. The typical orthographic projection is just a special case where the projection rays are perpendicular to the image plane. However, every parallel projection can be represented by an affine shear transformation followed by a standard orthogonal projection.
Im convinced I could get along just with the 4x4matrix in unity(or in any other 3d environment really).
Yes. Using default GL conventions here, all you have to do is to take the standard ortho matrix, post-multiply it by an appropriate shear matrix and use that as the projection matrix.
I'm creating my game with dynamicly generated terrain. It is very simple idea. There are always three parts of terrain: segment on which stands a player and two next to it. When the player is moving(always forward) to the next segment new one is generated and the last one is cut off. It works wit flat planes, but i don't know how to do it with more complex terrain. Should I just make it have the same edge from both sides(for creating assets I'm using blender)? Or is there any other option? Please note that I'm starting to make games with unity.
It depends on what you would like your terrain to look like. If you want to create the terrain pieces in something external, like Blender, then yes all those pieces will have to fit together seamlessly. But that is a lot of work as you will have to create a lot of pieces that fit together for the landscape to remain interesting.
I would suggest that you rather generate the terrain dynamically in Unity. You can create your own mesh using code. You start by creating an object (in code), and then generating vertex and triangle arrays to assign to the object, for it to have a visible and sensible mesh. You first create vertices at specific positions and then add triangles that consist of 3 vertices at a time. If you want a smooth look instead of a low poly look, you will reuse some vertices for the next triangle, which is a little trickier.
Once you have created your block's mesh, you can begin to change your code to specify how the height of the vertices could be changed, to give you interesting terrain. As long as the first vertices on your new block are at the same height (say y position) as the last vertices on your current block (assuming they have the same x and z positions), they will line up. That said, you could make it even simpler by not using separate blocks, but by rather updating your object mesh to add new vertices and triangles, so that you are creating a terrain that is just one part that changes, rather than have separate blocks.
There are many ways to create interesting terrain. One of the most often used functions to generate semi-random and interesting terrain, is Perlin Noise. Another is his more recent Simplex noise. Like most random generator functions, it has a seed value, which you can keep track of so that you can create interesting terrain AND get your block edges to line up, should you still want to use separate blocks rather than a single mesh which dynamically expands.
I am sure there are many tutorials online about noise functions for procedural landscape generation. Amit Patel's tutorials are good visual and interactive explanations, here is one of his tutorials about noise-based landscapes. Take a look at his other great tutorials as well. There will be many tutorials on dynamic mesh generation as well, just do a google search -- a quick look tells me that CatLikeCoding's Procedural Grid tutorial will probably be all you need.
So, I'm attempting to create a simple dynamic endless terrain using simplex noise.
So far I've got the noise working just fine - however I am having issues with the terrain having discontinuities at the edges. At first I thought this was due to the fact that I was not calling SetNeighbors on the Terrain objects, but adding this did not seem to yield any improvement.
terrain.GetComponent<Terrain>().SetNeighbors(left, top, right, bottom);
This problem seems to be caused by the slight differences in height between each terrain position - but making these set the same will effect the terrain quality (will reduce how jagged the terrain can be in certain cases) and generally seems inelegant. I've been going through the unity docs trying to find how to address this, but have yet to find anything.
Is there something I'm missing? Or is my only option to fiddle the heights on one of the sides to match the other?
Thanks for reading, appreciated as always.
Terrain image for reference
A couple things-
First, make sure you're setting SetNeighbors() on ALL the terrain objects, not just one.
Secondly, if the terrain don't match up exactly, it either means that the terrains aren't calculating their data quite correctly, or there's some floating point error going on. However, I have a suspicion that it's the first one, given that manually changing the points affects the quality. Make sure you know that terrains have n^2 + 1 points, and also make sure that the point to query from your simplex function with is calculated in world space.
If you can't figure it out, post your code and I'll take a look.
Also, your terrain might look better if you used octaved (a.k.a factal) noise on your Simplex noise function, depending on what you're looking for.
Cheers!
A recent question here made me think of SceneKit again, and I remembered a problem I never solved.
My app displays antenna designs using SK. Most antennas use metal rods and mesh reflectors so I used SCNCylinder for the rods, SCNPlane for the reflector and SCNFloor for the ground. The whole thing took a couple of hours, and I'm utterly noob at 3D.
But some antennas use wires bent into arcs or helixes, and I punted here and made crappy segmented objects using several cylinders end-to-end. It looks ass-tastic.
Ideally I would like a single object that renders the arc or helix with a cylindrical cross section. Basically SCNTorus, but with a start and end angle. This post talks about using a UIBezierPath in SK, but it uses extrude to produce a ribbon-like shape. Is there a way to do something similar but with a cylinder cross section (like a partial SCNTorus)?
I know I can make a custom shape by creating the vertexes (and normals and such) but I'm hoping I missed a simpler solution.
An arc you can do with SCNShape. Start with the technique from my other answer to get an extruded, ribbon-like arc. You'll want to make sure that the part where your path traces back on itself is offset by a distance the same as your extrusion depth, so you end up with a shape that's square in cross section.
To make it circular in cross section, use the chamferProfile property — give it a path that's a quarter circle, and set the chamfer radius equal to half the extrusion depth, and the four quarter-circle chamfers will meet, forming a circular cross section.
A helix is another story. SCNShape takes a planar path — one that varies in only two dimensions — and extrudes it to make a three-dimensional solid. A helix is a path that varies in three dimensions to start with. SceneKit doesn't have anything that describes a shape in such terms, so there's no super simple answer here.
The shader modifier solution #HalMueller alludes to is interesting, but problematic. It's simple to use a modifier at the geometry entry point to make a simple bend — say, offset every y coordinate by some amount, even by an amount that's a function of why. But that's a one-dimensional transform, so you can't use it to wrap a wire around on itself. (It also changes the cross section.) And on top of that, shader modifiers happen on the GPU at render time, so their effects are an illusion: the "real" geometry in SceneKit's model is still a cylinder, so features like hit testing apply to that and not to the transformed geometry.
The best solution to making something like a helix is probably custom geometry — generating your own vertex data (SCNGeometrySource). The math for finding the set of points on a helix is pretty simple if you follow that shape's definition. To wrap a cross section around it, follow the Frenet formulas to create a local coordinate frame at each point on the helix. Then make an index buffer (SCNGeometryElement) to stitch all those points into a surface with triangles or tristrips. (Okay, that's a lot of hand-waving around a deep topic, but a full tutorial is too big for an SO answer. This should be enough of a breadcrumb to get started, though...)
Here are some starting points that might help.
One approach would be to use more cylinders and make them shorter. That's the same idea behind the various segmentCount properties on the SCNGeometry primitives. Can we see a screenshot of the current linked cylinders version?
If you increase the heightSegmentCount, you could use the approach outlined here: scenekit, how to bend an object.
I just took a look at SCNShape. I was thinking you could use a shader modifier to warp the extruded shape into a circular cross section. But SCNShape doesn't seem to expose a segment count property, which I think you'd need to create enough extrusion segments for a good look. The chamferRadius and chamferProfile properties look interesting. I wonder if you could use those to create an extrusion that looks good.