# Is there a way to set roughness transmission mipmap resolution?

**URL:** <https://discourse.threejs.org/t/is-there-a-way-to-set-roughness-transmission-mipmap-resolution/28145>\
**Category:** Questions\
**Tags:** pbr\
**Created:** [July 19, 2021, 10:27am UTC](https://discourse.threejs.org/t/is-there-a-way-to-set-roughness-transmission-mipmap-resolution/28145 "2021-07-19T10:27:56Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![drcmda](https://avatars.discourse-cdn.com/v4/letter/d/91b2a8/32.png) [@drcmda](https://discourse.threejs.org/u/drcmda)\
**Post date:** [July 19, 2021, 10:27am UTC](https://discourse.threejs.org/t/is-there-a-way-to-set-roughness-transmission-mipmap-resolution/28145/1 "2021-07-19T10:27:56Z")

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It currently looks really chunky [Basic demo (forked) - CodeSandbox](https://codesandbox.io/s/basic-demo-forked-on01j?file=/src/App.js)

 ![Screenshot 2021-07-19 at 12.19.14](https://canada1.discourse-cdn.com/flex035/uploads/threejs/original/3X/a/e/aecf9eff18cd11b6b3d9638af36544446d3b4cdf.jpeg)

the fat pixels are also flipping as the transmission surface moves around. is there any way to mitigate this?

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**Author:** ![orion\_prime](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/orion_prime/32/15785_2.png) [@orion\_prime](https://discourse.threejs.org/u/orion_prime)\
**Post date:** [July 20, 2021, 11:20am UTC](https://discourse.threejs.org/t/is-there-a-way-to-set-roughness-transmission-mipmap-resolution/28145/2 "2021-07-20T11:20:59Z")

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i think some of the devs are already working on the improved version [https://twitter.com/superhoge/status/1417390236527566850](https://twitter.com/superhoge/status/1417390236527566850)  
might just have to wait

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**Author:** ![donmccurdy](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/donmccurdy/32/33209_2.png) [@donmccurdy](https://discourse.threejs.org/u/donmccurdy)\
**Post date:** [July 20, 2021, 8:26pm UTC](https://discourse.threejs.org/t/is-there-a-way-to-set-roughness-transmission-mipmap-resolution/28145/3 "2021-07-20T20:26:10Z")

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At present the transmission render target is a fixed 1024x1024 (with lower mips used for rougher surfaces, I believe) —

> <https://github.com/mrdoob/three.js/blob/ec5fb63a0b557474844f458065e5b26a22667e4e/src/renderers/WebGLRenderer.js#L1241-L1248>

I think making it configurable could be useful, but it is not totally straight-forward: the texture must be POT square in WebGL 1 (i.e. cannot generally be the same resolution as the viewport). There’s a little discussion in [https://github.com/mrdoob/three.js/pull/21884](https://github.com/mrdoob/three.js/pull/21884), and more improvements may be possible with WebGL 2.

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**Author:** ![trusktr](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/trusktr/32/13726_2.png) [@trusktr](https://discourse.threejs.org/u/trusktr)\
**Post date:** [February 12, 2023, 2:03am UTC](https://discourse.threejs.org/t/is-there-a-way-to-set-roughness-transmission-mipmap-resolution/28145/4 "2023-02-12T02:03:19Z")

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We really need this, especially for non-game experiences (f.e. glass on a UI).

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<div class="post-metadata">

**Author:** ![drcmda](https://avatars.discourse-cdn.com/v4/letter/d/91b2a8/32.png) [@drcmda](https://discourse.threejs.org/u/drcmda)\
**Post date:** [February 12, 2023, 11:03am UTC](https://discourse.threejs.org/t/is-there-a-way-to-set-roughness-transmission-mipmap-resolution/28145/5 "2023-02-12T11:03:57Z")

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> <https://github.com/mrdoob/three.js/pull/25483>
>
> \*\*Description\*\*
> 
> The current transmission shader technique makes the 0.25-0.75… roughness ranges pretty unusable due to the artefacts.
> This PR implements @N8python's \[shader\](https://www.shadertoy.com/view/Dl2SDW) for sampling the texture using bicubic filtering.
> 
> !\[Screen\_Shot\_2023-02-11\_at\_3 53 48\_PM\](https://user-images.githubusercontent.com/97088/218288515-b991be6d-58a4-4db1-9e1a-be4e733dbdac.png)
> 
> (Left side: bilinear, Right side: bicubic)
> 
> Haven't done performance comparisons yet.

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**Author:** ![dsine-de](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/dsine-de/32/41322_2.png) [@dsine-de](https://discourse.threejs.org/u/dsine-de)\
**Post date:** [October 30, 2023, 8:37am UTC](https://discourse.threejs.org/t/is-there-a-way-to-set-roughness-transmission-mipmap-resolution/28145/6 "2023-10-30T08:37:35Z")

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This has been reverted in newer releases, right? I’m currently having the same problem.

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**Author:** ![renaud](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/renaud/32/3805_2.png) [@renaud](https://discourse.threejs.org/u/renaud)\
**Post date:** [December 5, 2023, 10:55am UTC](https://discourse.threejs.org/t/is-there-a-way-to-set-roughness-transmission-mipmap-resolution/28145/7 "2023-12-05T10:55:09Z")

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Hi, is it possible to set the size of transmission render target ?

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**Author:** ![donmccurdy](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/donmccurdy/32/33209_2.png) [@donmccurdy](https://discourse.threejs.org/u/donmccurdy)\
**Post date:** [December 5, 2023, 3:12pm UTC](https://discourse.threejs.org/t/is-there-a-way-to-set-roughness-transmission-mipmap-resolution/28145/8 "2023-12-05T15:12:57Z")

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No, resizing the transmission render target is not currently supported.