8 votes
Accepted

How do I calculate the normals of a point group?

(Using Blender 3.6.5) Documentation: Preliminary remarks: As very well explained by Mr A in his proposal, Principal Component Analysis is a well adapted framework for this class of problems. One part ...
StefLAncien's user avatar
  • 3,652
6 votes
Accepted

Why multiply a normal?

A normal is pointing outwards of a geometry perpendicular to its plane (in case of a vertex the mean of its connected edges/faces) and it has a length of 1. The Offset in the Set Position node is what ...
Gordon Brinkmann's user avatar
5 votes
Accepted

Align instances along curve

capture the curve tangent and use it as a vector input for the align euler to vector node
Alex's user avatar
  • 2,633
5 votes

How do I calculate the normals of a point group?

There is a statistical technique called Principal Component Analysis (PCA) that fits this problem. It helps in data analysis by expressing the data in a new coordinate system that captures the ...
Mr A's user avatar
  • 1,860
5 votes

How do I calculate the normals of a point group?

I don't believe this is a solvable problem in its fully general form, where we can feed an algorithm a set of any points, in any order, in any position, and get the same face normal Blender provided ...
Nathan's user avatar
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5 votes
Accepted

How to get Vector Length in the compositor?

Yup. Just transcribe the expression, and group it up:
Robin Betts's user avatar
  • 76.5k
4 votes

How do I automatically rotate and move a camera mapped texture?

You can use object properties to counter the rotation and movement of the object. For the simplest case, position the camera in top orthographic view, rotate the object around Z axis and move it (...
Markus von Broady's user avatar
4 votes

How do I calculate the normals of a point group?

(Using Blender 3.6.5) This proposal is based on the Convex Hull node applied on a subset of the input geometry extracted with a Separate Geometry node. The sought normal per subset is the normal to ...
StefLAncien's user avatar
  • 3,652
3 votes

How do I calculate the normals of a point group?

We know that the general case can not be solved. But, we can try to do something if: all points of a group are not colinear the center point of a group is not at the same position as one point of ...
lemon's user avatar
  • 60.3k
3 votes
Accepted

Rotation of instances aligned to curve tangent and normals of another object

You can for instance do: First orient leaves top (Z) along the surface normal. Then orient them to the curve tangent (rotating around the previous Z). And optionally add some random (-pi/2 to pi/2) ...
lemon's user avatar
  • 60.3k
3 votes
Accepted

How to find the angle between surface normal and World Space Z up vector

We can find the green angle, in shader nodes, by taking the arccosine of the dot product of the world space normal and the world space up vector (which is, I imagine, 0,0,1, but if you're treating ...
Nathan's user avatar
  • 24.6k
3 votes

Why multiply a normal?

This group shows all the signs of having been created 'The Artist's Way', by improvisation, trial and error, so, from a mathematical point of view, your puzzlement is perfectly reasonable. Normals The ...
Robin Betts's user avatar
  • 76.5k
3 votes
Accepted

How do I automatically rotate and move a camera mapped texture?

Thanks to softyoda yoann's suggestion to use the UV project modifier I tried to use object mapping instead of window/camera mapping. Here's what I came up with: I've attached the cylinder to an ...
Brockoli Bruce's user avatar
2 votes

How do I automatically rotate and move a camera mapped texture?

Camera texture coordinates are meant for exactly what you show as current result. They are not meant for situations when you need the textures to move with the object. If you need the texture to move ...
Martynas Žiemys's user avatar
2 votes

Is it possible to manipulate with coordinate systems in geonodes?

i want to multiply by 0 part of the velocity vector, that points from center of sphere1 to center of sphere2. The dot product of two normalized vectors is the projection of one vector onto the other (...
Nathan's user avatar
  • 24.6k
2 votes

rotating along directional vector producing unexpected result

The reason it doesn't work is because when the edges are converted to points, they don't have "edge vertices" anymore (as they are not "edges"). To fix this, you want to capture ...
shmuel's user avatar
  • 1,615
2 votes

How to find the angle between surface normal and World Space Z up vector

Assuming $\vec{e}_Z$ is the unitary world up "normal" and $\vec{n}$ is the unitary surface normal, use the cross product to get the sine of green angle $\theta$ as: $\left| \sin{\theta} \...
StefLAncien's user avatar
  • 3,652
2 votes

Rotation of instances aligned to curve tangent and normals of another object

Here is my solution with curve to points and these points rotation, aligned to normals of another object. It's a bit messy, sorry for that! At the bottom you see my solution for different rotation for ...
Rolando's user avatar
  • 57
2 votes
Accepted

Why does StoreNamedAttribute's Vector Type for UVMap not work in place of 2DVector type?

(Using Blender 3.6.8) It seems that in the Shading Editor, the UV Map node is expecting a 2DVector type, and that if the attribute UVMap is a Vector (i.e. 3D), it is not identified as a valid UVMap. ...
StefLAncien's user avatar
  • 3,652
1 vote

How to set the normal value of a point on a spline?

okay. so number one: the tangent of the spline not the normal so your question is wrong. number two (the answer to whatyour actually wanted): you could use s switch node between the 'curve tangent' ...
shmuel's user avatar
  • 1,615
1 vote

How to reference rotation of every instance

The rotation you want to reach is given by an empty in this example. Invert instance current rotations and rotate the empty rotation by it. So that we have the rotation to reach from each instance ...
lemon's user avatar
  • 60.3k
1 vote

Aligning the long side of an object to a specific axis with geometry nodes

I'm not sure if this is what you're looking for, but in your case the object gets the rotation via the transform properties. Therefore, it would be possible to invert exactly this rotation and thus ...
quellenform's user avatar
  • 35.4k
1 vote
Accepted

Subdivide and fold selected mesh edges by a fixed angle along the edge normal with geometry nodes?

Divide Edges & Offset by Angle The Problem [btw the following is in response to the question and I will repeat things that I’ve mentioned in the comments] The main problem you are facing is: you ...
shmuel's user avatar
  • 1,615
1 vote

How to replace Attribute Vector Math in this situation?

Following Entagma's formulation.. In GN Fields, to store an attribute on the points of the modified object representing a clamped linear (0->1) gradient between the locations of external objects A ...
Robin Betts's user avatar
  • 76.5k
1 vote
Accepted

Dyamically Keep Edge-Aligned Instances a Fixed, Specified Distance From Main Geometry Edge Vertices Using Geometry Nodes

To get the points you can first split all edges of the target geometry: Now we need a scale value for the Scale Elements node that gives the desired distance from the vertices. Dividing a value $v$ ...
Hulifier's user avatar
  • 6,048
1 vote
Accepted

How to create an silhouette/outline mask

Soo after a lot of research I have found two viable solutions for this. First one, not really practical but will still work: For this you will create a cryptomatte in compositing and feather the edges ...
Poppi's user avatar
  • 117
1 vote
Accepted

Temporal Denoising: EXR image sequence node in the compositor is missing vector output

When rendering, you need to set your File Output node to OpenEXR MultiLayer. Select the node, and press N to open the sidebar, if it isn't already open, the click the Node tab. Set the fileformat to ...
Titanius Anglesmith's user avatar
1 vote
Accepted

Rotation of a profile using the "Curve to Mesh" node in Geometry Nodes

Resetting the Curve Tilt to $0$ will not help you, because when using Curve to Mesh the tangents of the curve ultimately decide the orientation of the mesh. So in ...
quellenform's user avatar
  • 35.4k
1 vote

How to Create Voronoi Texture with Vector Colors and Distance-Based Distortion in Blender

The Minimum operation of a Vector Math node performs component wise, using this will produce very short vectors with mingled coordinates. You need to compare the lengths of the vectors. First create a ...
taiyo's user avatar
  • 3,384
1 vote
Accepted

Is it possible to manipulate with coordinate systems in geonodes?

Let me first try to Steelman your question: This setup generates two balls and two arrows on the 2nd ball (called 'Sphere 2'). One, white arrow is just an arbitrary (random in this case) direction ...
Markus von Broady's user avatar

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