1
$\begingroup$

I'm stuck in a problem where I can't figure out how to extrude the bottom of an object in the way shown below. I'm new to blender geometry node, been trying Set Position, Extrude Mesh and Scale Element but still can't get the result desired. Didn't know the keyword to research the problem. It would be great if anyone could teach me on how to do it. enter image description here

$\endgroup$
4
  • $\begingroup$ Hello, 0292.. do you mean any object, (like a GG edge-slide) or this one in particular? $\endgroup$
    – Robin Betts
    Commented Apr 24 at 17:28
  • $\begingroup$ Yes, i mean it edge-slide. It would be great if there was a solution for any object rather than just this one in particular. If not possible, then the method for this case is also good help. I searched that blender geometry node does not support extrude by normal yet. Correct me if i'm wrong. $\endgroup$ Commented Apr 25 at 3:28
  • $\begingroup$ For clarification: do you want to extrude (i.e. create new points, edges, faces, not moving existing ones) or to scale (i.e. in your case, slide end point of edges in each edge direction) ? $\endgroup$ Commented Apr 25 at 6:02
  • $\begingroup$ Yes, I'm actually want to extrude it as you said: slide end point of edges in each edge direction. $\endgroup$ Commented Apr 25 at 6:36

2 Answers 2

2
$\begingroup$

Here is an alternative method if you instead of Extrude or Edge Slide want to have something that behaves like scaling in Edit Mode with the Transform Pivot Point set to Active Element, by choosing a vertex from which you want to scale everything (well, I said instead of Edge Slide but scaling an edge away from or towards an endpoint is basically edge sliding):

Use a Sample Index node to determine which vertex you want to be the scaling pivot. Then subtract this vertex position from all positions to get the vectors from the pivot to the other vertices, then scale those vectors and add the pivot again afterwards (scale by > 1 to increase, by < 1 to decrease the size). The result goes into a Set Position node to move the vertices. By switching the Index you can switch between pivot points.

gn nodetree scaling pivot

This way you can scale the geometry "away" from the vertex with the chosen index.

scaling pivot

Of course this also works if you want to define the center of an edge or a face as pivot point just by switching the Sample Index node to a different domain like Edge or Face rather than Point.

$\endgroup$
1
  • 1
    $\begingroup$ Work like a charm! Thank for clearly explain and sharing! $\endgroup$ Commented Apr 25 at 10:20
1
$\begingroup$

you can use this node setup:

enter image description here

and play around with the 2 values in the red nodes.

$\endgroup$
2
  • $\begingroup$ Sorry for lacking info, actually i want to extrude it's bottom edge loop, my object doesn't have bottom face. But by your answer i get the idea now. Thanks for your help. $\endgroup$ Commented Apr 25 at 3:21
  • $\begingroup$ no problem, just open a new answer with your additional detail - you may open as many questions as you want! $\endgroup$
    – Chris
    Commented Apr 25 at 4:54

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .