---
title: "Resumable Rendering Workflow"
canonical: "https://documentation.chaos.com/space/VC4D/116852322/Resumable%20Rendering%20Workflow"
format: markdown
---
This page is a tutorial on how to use resumable rendering with V-Ray for Cinema 4D.


## **Overview**

---

Resumable rendering allows you to resume incomplete renders from where they left off in the previous session. The rendering may have stopped due to any number of reasons such as a power failure or having the job bumped off a machine or a render farm, or perhaps you stopped the render manually and want to start from where you left off.

Resumable rendering uses sidecar files for tracking checkpoints. For **Bucket** sampling, it uses a *.vrimg* file, and for **Progressive** sampling, it uses a *.vrprog* file.

Want to follow along but don’t have a license?


> Macro (ui-button)





## **How it Works **

---

Resumable renders are possible with both Bucket and Progressive [Image Sampler types](https://docs-chaos.atlassian.net/wiki/spaces/VC4D/pages/116855825):

With **Bucket** rendering, an additional *.vrimg* file is written, storing the data of the completed buckets. When resuming the render, V-Ray reads the *.vrimg* file to determine which buckets still need to be rendered and continues to calculate what is left to complete the image. Another great ability of this feature is that the [Light Cache](https://docs-chaos.atlassian.net/wiki/spaces/THEORY/pages/116719627) data is saved within the partial image file so that the light cache does not need to be recalculated when the render resumes.

With the **Progressive** image sampler, the state of the render is saved to an additional resumable *.vrprog* file. When using the Progressive Image Sampler, setting the **Autosave Interval (minutes)** to anything higher than 0 is useful so V-Ray can write out the *.vrprog* files during rendering, in case the process is unintentionally stopped. However, setting the Autosave Interval (minutes) value too low (below a couple of minutes for example) may slow the render process.

If V-Ray finds a* .vrprog* file or a partially completed* .vrimg* file for the current frame, the rendering resumes from where it left off. If not, V-Ray starts a new render and a resumable file is then saved.

> Macro (ui-text-box)
> 
> Resumable Rendering is also compatible with [Distributed Rendering](https://docs-chaos.atlassian.net/wiki/spaces/VC4D/pages/116851098).

## **Workflow**

---


## **Notes**

---

- Light Cache data is saved in the resumable files, but the Irradiance Map (or any other [GI map](https://docs-chaos.atlassian.net/wiki/spaces/THEORY/pages/116719621)) is not, and will need to be recalculated when resuming the render. The rendering should still continue from where it was stopped, after the GI data is recalculated.
- Enable the Resumable Rendering option before starting a new render, not only when resuming.
- To start a new render, the old .vrimg*/.vrprog* resumable rendering file should be deleted.
- The scene should not be changed between stopping and resuming, except for the Progressive sampling options (Min Subdivs, Max Subdivs, Max. Render Time in Min, Noise threshold, Ray Bundle Size).
- When [Test Resolution](https://docs-chaos.atlassian.net/wiki/spaces/VC4D/pages/116855676) is enabled, Resumable Rendering is temporarily disabled.