# ray cast only mode in UniformGridRepresentation volume rendering have low quality compare to GPU based mode

**URL:** https://discourse.paraview.org/t/ray-cast-only-mode-in-uniformgridrepresentation-volume-rendering-have-low-quality-compare-to-gpu-based-mode/17006
**Category:** ParaView Support
**Tags:** vtk
**Created:** [July 24, 2025, 3:31pm UTC](https://discourse.paraview.org/t/ray-cast-only-mode-in-uniformgridrepresentation-volume-rendering-have-low-quality-compare-to-gpu-based-mode/17006 "2025-07-24T15:31:39Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![LeonHaoWI](https://discourse.paraview.org/user_avatar/discourse.paraview.org/leonhaowi/32/16785_2.png) [@LeonHaoWI](https://discourse.paraview.org/u/LeonHaoWI)
#### Post date: [July 24, 2025, 3:31pm UTC](https://discourse.paraview.org/t/ray-cast-only-mode-in-uniformgridrepresentation-volume-rendering-have-low-quality-compare-to-gpu-based-mode/17006/1 "2025-07-24T15:31:39Z")

</div>

I’m using ParaView 5.13.1 on windows(local) to volume render a volume data(from a CT scan).  
Found that the image quality is very low in ray cast only mode(CPU only) compare to GPU based mode.

 ![image](https://discourse.paraview.org/uploads/default/original/3X/d/d/dd416a3feb2b2ad8d3b58979f6257b4dc72759d3.jpeg)  
 ![image](https://discourse.paraview.org/uploads/default/original/3X/1/3/13e8f131f9b87437edfc4c9f9401dff7a9edef64.jpeg)  
When enable ray tracing(OSPRay raycaster), the result is fine.

Have tried set preview resolution(View-\>Preview-\>3840\*2160).  
Have tried adjust level of detail(LOD) in interactive rendering options.

Is this a bug?