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I'm trying to calculate a set of points in this Combine XYZ node and I want to dynamically create a mesh of vertices from these points. How do I do this? I mean it's possible to pass Combine XYZ to Set Position node but that assumes the vertices already exist. I'm not sure if Points to Vertices or something similar does the job? I need something that converts these points from Combine XYZ node to an actual mesh.

I know I can easily do this with XYZ Math Surface but I'm curious to know If geometry nodes is capable of dynamically generating such a mesh as well. It has the advantage that I can also animate it rather than a static XYZ Math Surface

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This is the node setup I have for the sphere

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UPDATE:

I just realized using Position node and Grid node really do answer my question:

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    $\begingroup$ the problem is that you have "just" points. For a mesh you need edges and faces (and as you know you can only see faces, if you render). And you don't have these informations if you have just points...of course you can set this points (e.g. from a point cloud), but this doesn't mean that you have a working mesh. $\endgroup$
    – Chris
    Jul 27, 2022 at 10:24
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    $\begingroup$ your wish is my command.... :D $\endgroup$
    – Chris
    Jul 27, 2022 at 11:20
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    $\begingroup$ node setup: [1]: i.stack.imgur.com/E22OH.jpg $\endgroup$
    – Chris
    Jul 27, 2022 at 11:27
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    $\begingroup$ result: [1]: i.stack.imgur.com/CjJSx.gif -> yellow: GN ,"normal": Math surface $\endgroup$
    – Chris
    Jul 27, 2022 at 11:28
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    $\begingroup$ friggin awesome! you're the man! i wanted to verify it with the nautilus but got lazy coz there are too many nodes hahahaha thanks a lot for showing it! :D $\endgroup$
    – Harry McKenzie
    Jul 27, 2022 at 11:31

1 Answer 1

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These nodes don't work in this way. When you see the round socket it is ok, data travels from left to right, as you expect. But when it comes to diamond sockets, the data travels back from right to left to the source to get the data for the node with the round socket. That means that the node with round socket initiates the flow in diamond sockets. Without it, you will not have any data. So this is your mistake:

I have calculated a set of points in this Combine XYZ vector

No, you haven't calculated anything, if you don't have vertices (or shall we say Data Domain), you don't have its coordinates.

So the question is what are you trying to achieve. If it is a mesh, connected with edges and faces, you have to define this mesh, because at this time you can't build mesh out from points. So you can create a basic shape and move it's points using set position node.

If you want to make a point cloud, you should define a size of this point cloud, how many points in it. Simply make a mesh line and convert it to point cloud using Mesh to Points node:

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As I understand, you are trying to do like this:

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  • $\begingroup$ okay I updated the question. actually i have a set of parameterized equations that i want to use to dynamically create any shape. how do i realize such a mesh? i want to know how to do it with geometry nodes because i already know how to do it with XYZ Math Surface $\endgroup$
    – Harry McKenzie
    Jul 27, 2022 at 10:10
  • $\begingroup$ I haven't much to add in my answer, except when you are using spline parameter, data domain should be spline. And I suppose it is not a domain that you want to use. Maybe you have an image that are you trying to achieve? Can you share the nodes as well, so I can play with blend-exchange.com $\endgroup$
    – Crantisz
    Jul 27, 2022 at 10:14
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    $\begingroup$ I've updated the answer $\endgroup$
    – Crantisz
    Jul 27, 2022 at 10:28
  • $\begingroup$ hmmm using a grid is a workaround. it will only create a half sphere blend-exchange.com/b/24ydxSN7 and besides it cannot cater to complex shapes such as the presets under XYS Math Surfaces. So I should probably ask if Geometry is even designed for such tasks or probabaly it is not right? $\endgroup$
    – Harry McKenzie
    Jul 27, 2022 at 10:50
  • $\begingroup$ Edit map range, for second half $\endgroup$
    – Crantisz
    Jul 27, 2022 at 11:03

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