Arrow shader using curves

Support Materials and Textures
1

Hi. I am trying to achieve a shader for extruded curves that allows me to generate arrows while I extrude the curve.

arrow path
arrow path826Ă—666 45.1 KB

I started with a Wave texture and plugged the UV node hoping this would help me to get the lines following the curve without deforming, but that is not happening.

I planned to mirror the strips with some math nodes and generate the arrows.

Is this possible?

Thank you

2

Hi,

Can you share your .blend file?

3

Well yes there are quite some ways to do it. Eg this one.

ArrowShader
ArrowShader1504Ă—986 412 KB

4 Likes
4

Thank you so much. Do you think there is a way to avoid the arrow from bending and wobble? It is for an infographic, and although this seems to be the right approach, it might look a bit psychedelic.

I appreciate any help you can provide.

5

Well to some degree by changing the splinetype to poly. Beside that its uv based and these compress and stretch along the surface.

1 Like
6

I will try out your proposal. It might work due to my lines are just straight with a radius when changing directions.

1 Like
7

No, I do not think this work well:

arrow
arrow1798Ă—1318 253 KB

The shader its inconsistent, and the stripes break at some points. Also, depending on the handle properties, they stretch or shrink. I am unsure if there is a command to make all handle the same length.

I leave the file here in case someone knows
how to procedurally add arrows to an extruded curve.

arrow.blend (1.1 MB)

Thank you

8

You can use geometry nodes to improve the effect:

  1. deactivate extrude
  2. resample the curve in geometry nodes with equal length
  3. generate UV coordinates from the spline factor
  4. set material
    image
    image2569Ă—1660 392 KB

In the shader, use the attribute which is output by the geometry nodes setup as coordinates

image
image1855Ă—574 97.5 KB

(Blender version 3.5.0
arrow_v02.blend (1.1 MB))

Edit: Alternatively, you could use the length instead of the factor as the x-coordinate. Then your arrows won’t stretch when you extrude the curve.

image
image1521Ă—694 111 KB

3 Likes
9

What about making a single arrow object and using an array modifier, fitting to the curve?

1 Like
10

Well its UV based. The streching and shrinking is due to that, so you have to accept on how blender places the uvs for curves if you want to use curves. But its just that the point offsets have to be even along the curve, not the biggest problem IMO. UV based approaches will always have distortion, even if the uv mapping is adapted to the segment length. You might choose instances along the curve as @Tedri_Mark suggested but then you get overlaps in curved regions instead.

11

Like this?

image
image2160Ă—676 131 KB

Will have the same deformation problems.

But you could use geometry nodes (again):

image
image2218Ă—1426 339 KB

arrow_v04.blend (1.1 MB)

3 Likes
12

Nice, I did wonder it that might be the case :slight_smile:

1 Like
13

Thank you for your contribution. The whole point is to have it shader based. This is how we solved it last time when we could not do the shader option.

I would like to not deviate from the shader approach.

14

Are geometry nodes the problem? This version here still creates the arrows using a shader, not additional geometry: Arrow shader using curves - #8 by LordoftheFleas

You will have to somehow resample the curve to get rid of the distortions…

1 Like