> ## 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.

# Optional: Periodic Lattice Test Problem

Now that you have learned about Periodic Lattices in nTop, feel free to try this optional problem with a review of the answer in the following lesson.

Given the starter file below, use your own **Custom****Unit****Cell**to

* generate a custom lattice infill across the implicit body variable labeled*Inner Body*
* add a custom texture across the variable labeled *Faces to Texture*

**Estimated Time to Complete:** 30 minutes

**Example File:**

[210\_16\_1 Starter–Optional Periodic Lattice Test Problem.ntop](https://files.learn.ntop.com/Courses/210%20Intro%20to%20Lattices/nTop%20Files/210_16_1%20Starter--Optional%20Periodic%20Lattice%20Test%20Problem.ntop)

*This file was last updated in nTop 3.38.4*