# HIL with Gazebo Garden and custom model

**URL:** <https://discuss.px4.io/t/hil-with-gazebo-garden-and-custom-model/39936>\
**Category:** Uncategorized\
**Created:** [July 30, 2024, 7:34am UTC](https://discuss.px4.io/t/hil-with-gazebo-garden-and-custom-model/39936 "2024-07-30T07:34:24Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![fc250](https://discuss.px4.io/user_avatar/discuss.px4.io/fc250/32/15542_2.png) [@fc250](https://discuss.px4.io/u/fc250)\
**Post date:** [July 30, 2024, 7:34am UTC](https://discuss.px4.io/t/hil-with-gazebo-garden-and-custom-model/39936/1 "2024-07-30T07:34:24Z")

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Hi guys,  
I am struggling to reduce the gap between Sim2World simulation using Gazebo Garden and PX4 1.15\_dev. I have noticed that SITL is overly idealistic when tuning gains for an offboard controller in Gazebo. Even with a correctly modeled and parameterized simulation, there is a significant discrepancy between simulated and real-world conditions.

I want to understand if developing a custom controller in SIH can help me reduce this gap. I am wondering if anyone has tried using SIH with Gazebo Garden or Harmonic. Is it possible to use SIH with Gazebo Garden? Can I use a custom model with SIH? Where in the PX4-Autopilot codebase would I find the relevant code for this ?