# Implicit Quadric model with Perlin or other noise applied
**URL:** https://discourse.vtk.org/t/implicit-quadric-model-with-perlin-or-other-noise-applied/8115
**Category:** Support
**Created:** [March 22, 2022, 11:55pm UTC](https://discourse.vtk.org/t/implicit-quadric-model-with-perlin-or-other-noise-applied/8115 "2022-03-22T23:55:23Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Spacetracker](https://discourse.vtk.org/u/Spacetracker)
#### Post date: [March 22, 2022, 11:55pm UTC](https://discourse.vtk.org/t/implicit-quadric-model-with-perlin-or-other-noise-applied/8115/1 "2022-03-22T23:55:23Z")
I create a complex implicit surface model with quadric function boolean combinations. I want to perturb or filter these individual smooth surfaces to make them bumpy or irregular with the Perlin function or something like it. Please point me to examples or suggestions. I have the examples from the VTK example sets, but the Perlin example is an Implicit surface type itself, not a modifier to others, it seems. Thanks.
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### Author:  [@Yohann\_Bearzi](https://discourse.vtk.org/u/Yohann_Bearzi)
#### Post date: [March 23, 2022, 1:32pm UTC](https://discourse.vtk.org/t/implicit-quadric-model-with-perlin-or-other-noise-applied/8115/2 "2022-03-23T13:32:11Z")
Do you want the surface to still be implicit after applying a Perlin noise? It sounds like it would be complicated to achieve that. I’m not sure you would still have a surface if the noise is also implicit.
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### Author:  [@Spacetracker](https://discourse.vtk.org/u/Spacetracker)
#### Post date: [March 23, 2022, 2:54pm UTC](https://discourse.vtk.org/t/implicit-quadric-model-with-perlin-or-other-noise-applied/8115/3 "2022-03-23T14:54:25Z")
I am using vtkQuadric as the base model so the surface is obviously smooth. Since I am using vtkImplicit Boolean with Difference that makes it more complicated. The vtkPerlinNoise builds a rough implicit surface somehow. I just want to add some roughness to my smooth surfaces, if possible. It would not be worth the effort for me to enhance or reimplement a rough Quadric. So I will just stick with the ideal surfaces. The polygonization has to be an actual rough surface, not a visual effect. Unless there is some other filter that will do that. Thanks
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### Author:  [@will.schroeder](https://discourse.vtk.org/u/will.schroeder)
#### Post date: [March 23, 2022, 3:04pm UTC](https://discourse.vtk.org/t/implicit-quadric-model-with-perlin-or-other-noise-applied/8115/4 "2022-03-23T15:04:05Z")
I’d add the roughness to the surface (polygonal mesh) or through a shader (I’m assuming here that you are extracting a surface.)