# How to use go.set() to set a vertex attribute of type Mat3?

**URL:** <https://forum.defold.com/t/how-to-use-go-set-to-set-a-vertex-attribute-of-type-mat3/83174>\
**Category:** Questions\
**Created:** [August 27, 2026, 9:36pm UTC](https://forum.defold.com/t/how-to-use-go-set-to-set-a-vertex-attribute-of-type-mat3/83174 "2026-08-27T21:36:55Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![vinicius](https://forum-defold.b-cdn.net/letter_avatar_proxy/v4/letter/v/bcef8e/32.png) [@vinicius](https://forum.defold.com/u/vinicius)\
**Post date:** [August 27, 2026, 9:36pm UTC](https://forum.defold.com/t/how-to-use-go-set-to-set-a-vertex-attribute-of-type-mat3/83174/1 "2026-08-27T21:36:55Z")

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I am trying to pass a Texture Transform 2D to my vertex shader. I set the Vertex Attribute in the material, have it declared and used in the shader. But when I try to set it using `go.set("#model", "transform2d", vmath.matrix4())` I get the error:

```lua
ERROR:SCRIPT: main/script.script:2: the property 'transform2d' of '#model' must be a boolean

```

In the [Material Manual](https://defold.com/manuals/material/#setting-custom-vertex-attribute-data), last paragraph of the section “Setting custom vertex attribute data” my understanding is that I should be using a `vmath.matrix4()`. The example given is actually very close to what I am trying to do but it doesn’t show the lua code for how to set the attribute.

Here is a reproduction of the problem

[set\_texture\_transform\_test.zip](https://forum.defold.com/uploads/short-url/cPMnmR0x8cWoC0iMv6tUHQqMIg.zip) (32.6 KB)

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<div class="post-metadata">

**Author:** ![vinicius](https://forum-defold.b-cdn.net/letter_avatar_proxy/v4/letter/v/bcef8e/32.png) [@vinicius](https://forum.defold.com/u/vinicius)\
**Post date:** [September 14, 2026, 2:09pm UTC](https://forum.defold.com/t/how-to-use-go-set-to-set-a-vertex-attribute-of-type-mat3/83174/2 "2026-09-14T14:09:48Z")

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Just an update to anyone coming here with the same question. It is [indeed a bug](https://github.com/defold/defold/issues/13094) and the devs are working on a fix, so far scheduled for release in version 1.14.0 but I guess that could still change. I will update this thread again once a working release come out.

Thanks Defold team!