> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ntop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# How to generate surface roughness with varying amplitude or frequency

## Objective:

If you're trying to use nTop to generate surface textures, this how-to example explains a high-performing and scalable workflow that applies to any object. Developing a unique texture can be non-intuitive initially, but once mastered, it can become the ultimate creativity tool in your arsenal.

Before starting this tutorial, check out the prerequisite [surface roughness](https://support.ntop.com/hc/en-us/articles/360060946514) workflow. By adding a few steps, we can control the texture's frequency with the [ramp function](/help-articles/knowledge-base/implicit-modeling/how-do-i-use-the-ramp-block). These examples are also shown in this article: [Generating surface textures with procedural modeling.](/help-articles/knowledge-base/textures/generating-surface-textures-with-procedural-modeling)

## Applies to:

* nTop
* Surface Texture
* Implicit Modeling
* Field-Driven Design

## Procedure:

1. Open the file built by the previous tutorial [Texturing - Surface Roughness.ntop](https://ntopology.box.com/s/j4zf9em8whl40en2wkffm4ywow8k9tkf).
2. Add a **Plane from Normal** block to the Notebook. The **Ramp** function will reference this Plane.
3. Add a **Ramp** block and use the Plane as the Scalar field input. Enter the remaining values, being sure to add units to **Out min** and **Out max**.
4. In the already existing **Multiply** block, replace the 1 mm with the ramp function. The surface roughness will generate, varying by the range of values per Out min and Out max.
5. We can also vary the noise frequency using a combination of ramp and remap functions. View the complete workflows in the example files.

![Using a Ramp block, the texture depth can be applied as a gradient that increases over the course of the body. The surface is smoother towards the starting reference plane and becomes increasingly rougher as the distance from the plane increases.](https://files.learn.ntop.com/help-articles/textures/360101314974.png)

## Download the Example file:

* [Surface roughness - Varying amplitude](https://files.learn.ntop.com/Support%20Article%20Example%20Files/Knowledge%20Base/Textures/Texture%20-%20Varying%20Amplitude.ntop).
* [Surface roughness - Varying frequency](https://files.learn.ntop.com/Support%20Article%20Example%20Files/Knowledge%20Base/Textures/Texture%20-%20Varying%20Frequency.ntop).

## Keywords:

*ramp surface texture roughness how-to noise varying*