# Questions tagged [mathematics]

Use of maths inside blender.

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### Mesh created with Geometry Nodes is slightly shifted compared to mesh created with XYZ Math Surface

I was trying to complete my answer for this question. I'm creating an XYZ Math Surface via Add > Mesh > Math Function > XYZ Math Surface using the following parametric equations: ...
• 13k
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### What would be the proper scaling of gravity when scaling up a simulation?

I have a rigid body simulation scaled up 16 times its normal size to get proper collisions and rotations of objects. I am having trouble pinpointing the correct scaling of gravity, however. If gravity ...
32 views

### Can you explain how to use Geometry Nodes to create a parametric mathematical object? [duplicate]

I want to generate a 3D surface from parametric equations X(u, v), Y(u, v), and Z(u, v) and ...
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### How to re-achieve the effect made by negative math nodes

Recently there was an update to blender that ended up breaking one of my shaders, the update made sure we dont get negative inputs for closure nodes which I need in order to make the shader work as ...
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### Generate equation from surface

Does Blender have already a way to generate equations from simple surfaces? In my case, I have a bowl and I want to find out the inner surface xyz equation of it. I've seen that you can do the other ...
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### Apply Local Rotation after Transform

I am currently writing my thesis essentially about Camera Re-Localization using SfM. To compare results and measure them properly, I created a dataset with ground truth in Blender. It works as follows:...
19 views

### How do I convert camera's rotation from Z-Up to Y-Up?

So I have this script that exports data on the location and rotation of the camera every keyframe to a json file, and this is working great but the problem is that I need to convert the rotation from ...
25 views

### Vector Math (Multiply) chosen axes x 1.0 vs Combine XYZ node?

I have a Geo Node housekeeping question today that I can't quite answer with what I've read/found. Disregarding specific use cases, which method is more expensive to isolate a one or two axes along a ...
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### How to make dynamic instance density in the viewport with geometry nodes?

I'm wondering if it's possible to make a scattering system with geometry nodes that would dynamically change the density of the viewport instances so that the total number of instances would stay the ...
1 vote
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### Rotate object to point another object with Geometry Nodes

I have a simple setup scene, as shown below: The mesh is called "Arrow" and the cube is called "Empty". Now all I want to do is rotate the Arrow so that it's Z points toward the ...
235 views

### How do I calculate sum per frame?

I'm trying to find a way to control the rotation speed of an object. First I tried rotating it using a driver and then multiplying that driver with a control value that ranges between 0 (standing ...
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### Texture animation with math nodes

starting from a texture image (B&W), I'd like to animate the movement of the white line by limiting its movement between the two black lines. Would a math node allow me to do this? I'm attaching a ...
44 views

### geo nodes Start/Stop Attribute

Hello i want to make a geo node setup where we define a Start and End frame and get an attribute value which starts from 0 at start frame then stop at certain value let's say 10 and just a few frames ...
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### How can I use convolution matrix in Shader Node

I want to use a convolution matrix so that I can create a Gaussian Blur for the image without it having too much noise. I saw someone upload it to BlendSwap and also something else here on ...
1 vote
45 views

I'm trying to make a procedural trail in geo-nodes. But I have no idea how to make trail follow mesh position. Somehow I have to calculate movement direction and set position of points according to ...
46 views

### Creating Toon Shader Nodes in Blender: Incorporating Brightness Classes to Determine Crosshatch Pattern

I'm looking for some help in Blender to create a shader that incorporates a crosshatched pattern. Some tutorials teach how to do it, but they use the same pattern, only changing its size or intensity ...
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313 views

### Calculate the offset needed to invert / collapse faces to center of a dodecahedron using geometry nodes

Calculate the offset needed to invert / collapse faces to center of a dodecahedron. I want to calculate the required offsets to have an object's "...
• 4,523
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### Trackball Behaviour With Modal Operator

I need to create a trackball like behaviour for a modal operator. Is there a possibility to implement this into the functionality by moving the mouse? I just need to know how the math works when ...
58 views

### How can I get the light direction vector without the roll values?

From watching videos and looking at other posts, it seems like the common way is to just straight up copy the sun's rotation values for the light direction vector. However, this also copies the roll (...
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### How to set the normal value of a point on a spline?

How does one go about setting the normals of individual points on a spline? Adding to that question, are these attributes listed on the spreedsheet window? Part of my confusion is figuring out the ...
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1 vote
60 views

### Rounded rectangle in shader editor?

How can I create a rounded rectangle with Width, Height, Radius parameters based on the UV coords? For example, on a simple plane
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### How can I change where the vertices are located on a curve using geometry nodes?

How can I change where the vertices are located on a curve using geometry nodes? Example: I have a curve line of 32mm and I want the vertices located at the points ...
• 4,523
1 vote
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### Generate Column and Line Charts Procedurally [duplicate]

I'm new to Blender and wanted some help with creating column charts and line charts, like you would in Excel. The need to be procedural I have hundreds of values for some charts, and altering each ...
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1 vote
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### How can I insert a custom implicit equation in blender, draw its associated 2D curve and then create a revolution solid out of it?

I want to write down a parametric equation for a curve and then create a solid out of it. I would like to know the procedure (the pipeline/workflow) on how to do this. Let me explain. I have an ...
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### how can I apply the index to all objects at once?

Hi how can I apply the index to all objects at once? I want to remove some faces from many cubes at once. Now this is happening in order 1.2,3,4, etc. I want to leave the upper and side face of all ...
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### can someone explain me the node setup in red and why does the -0.5 value keeps the plane from moving up and down?

I am trying to understand why the value of -0.5 stops the plane from moving vertically and how do
53 views

### What's the math behind cast modifier?

I can't find any documentation or article about it on the internet different from the information provided on the manual page. For me, Blender's documentation is not clear on what mathematical method ...
71 views

### Circle equation using sin and cos

I'm learning how to create plots with geometry nodes and math nodes but I'm confused why this isn't a circle that is created with 0,0 as the center axis.
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### Creating / 3D Printing large O-rings using geometry nodes

Creating / 3D printing large O-rings using geometry nodes I'm trying to create and 3D print large connected O-rings given its length, width, and height (that won't fit on the print bed circularly) ...
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### How to reproduce Blender's smooth shading?

Thanks to help of shmuel I made a setup for interpolating a normal in geonodes. Ideally, it would reproduce Blender's smooth shading exactly. So I reproduced the setup in the Shading nodes. In order ...
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### How can I convert the Multiply Add node in Blender 2.79?

I need to change node Multiply Add from Blender 4.0.2 to Blender 2.79 with math nodes. How i can do that?
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### Modelling surface diagrams

While working on a project in higher category theory, a branch of mathematics, I was lead to draw so-called "surface diagrams" similiar to those that can find in the following papers; page ...
1 vote
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### How can I create a formula for proportional scale in geometric nodes?

How do I create a formula so that the scale changes and immediately becomes the same? For example: I set the scale to 2 and in another transform I changed it to 0.5 so that it would become the ...
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### Help to understand why the sine wave from a curve line is not the same lenth of the curve line?

I have problem -Please help me to sole the problem of the length if you can tell me reason i will be gratfull
1 vote
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### Looking to scale along normals using geometry nodes using a texture as a scaling factor

Not sure how feasable this would be but as the title suggests, I'm looking for a way to shrink a mesh along the vertex normals using a height map for the scaling factor. Context: This is for an animal ...
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### How to visualise overlapping lines and attribute color based on frequency

I would like to visualize the datapoints, or lines in this case, that are overlapping, and assign 1) a color based on how many overlapping lines there are. Data is an import of a shapefile where i ...
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### Geometry Nodes: How limit function and activate the said function with an integer change or a click?

I'm making a scoreboard, and I want it to have a rotating animation that is activated once an integer value is edited. I have tried to rotate with tangent function, and it looks good, but I don't ...
78 views

### Is it possible to use a piecewise function in property drivers?

I have an object with keyframes on its Z-rotation so it rotates about its vertical axis. I want to have a driver on its X-position that takes the Z-rotation value, performs a modulo-operation on it to ...
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### How to calculate the minimum difference between 2 values in a range that wraps around itself using math nodes?

I made this illustration and used a circle for better visualization of what I mean. Basically you define the Min and Max values in the range (which end up being the same point) and the max possible ...
381 views

### How does the multiply color node work?

How does multiply shade node work? I've found similar question, but in that case it's a "difference" parameter. What about multiply then? I've tried to look for it in Blender documentation, ...
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### Add object on mesh face, geometry node

I ask for help in solving my problem. It is important for me to understand which nodes to use to calculate the location of an object's face and which bundle to transfer and indicate this position to ...
868 views

### Creating a concave dodecahedron using geometry nodes

I'm trying to create concave dodecahedron using geometry nodes I can create a dodecahedron Then add the edges. But how can I collapse the center vertices correctly?
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1 vote
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### Aligning the long side of an object to a specific axis with geometry nodes

I'm trying to make sure the long side of this object is always aligned with the x-axis, no matter what direction the source object is facing. I figured the max vector would probably be aligned ...
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1 vote
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### How do I fix XYZ Math Surface error "'NoneType' object is not subscriptable"?

I am trying to create an object using the Add > Mesh > Math Function > XYZ Math Surface option from the Add Mesh Extra Objects add-on. However, when I input my equation ...
• 275
60 views

### How to make roughness vary linearly along one axis for a vertex group?

I have a vertex group selected along a surface scratch and want to vary the roughness parameter in principled BSDF from lets say 0.5 at the start of the scratch to 0.2 at the end of the scratch ...
186 views

### Mathematically applying quaternion, octonion, and other alternative algebras to objects (to transform them) using geometry nodes

Mathematically applying quaternion, octonion, and other alternative algebras to objects (to transform them) using geometry nodes. I'm trying to take different 4D meshes/objects that are generated ...
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1 vote
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### How to ensure consistency when converting from quaternion to Eulers via Python?

My program must interpolate between two sets of quaternion fcurves by a given value. Normally, one would SLERP or LERP. However, my program includes the option to 'turn off' the individual x/y/z axes, ...
1 vote
245 views

### How to replace Attribute Vector Math in this situation?

Here I am following a tutorial (the hand reveal) where Entagma uses the Attribute Vector Math in Geometry Nodes in Blender 2.93.0 beta but I don't see it anymore in Blender 4.0 and, my question is, ...
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