Storing Data for Custom Renderer

What is the correct (preferred) way to store data for custom render engine?

As far I can see I have at least three options:

  1. Store it in a custom container and read/write it during plugin ReadDocument/WriteDocument functions.

  2. Store as UserData (Rhino.RhinoDoc.ActiveDoc.RenderSettings.UserData)

  3. And in the example “SampleCsCustomRednerSettingsSections” in the code it stores it in a data object (wich comes somehow from IRdkViewModel???):
    GetData(Rhino.UI.Controls.DataSource.ProviderIds.RhinoSettings, false, true) as RhinoSettings;

I am really not sure where it saves the data actually…

Thanks in Advance!


Hi, the simplest way is to use plug-in settings. Here is how the Raytraced mode saves settings for the Cycles render engine:

RcPlugin is the plug-in object for my plug-in:

While you are integrating your engine, please have a look at the ChangeQueue to build upon. This is the preferred way to start integrating your engine.

Let me know if you have any further questions regarding render engine integration, we’ll happily assist you as much as we can. (Didn’t notice I was using my personal account when writing above reply).

Ohhh, I didn’t realised that we have such a complex sample code.

This is Great!

Thank you.


It is not only sample code, it is the entire implementation of the Raytraced mode (: a reference implementation for render engine integration, if you will.

Sorry, yes, I wanted to admit it as it is - “sample” was a wrong word.

And it seems I was not clear in my first question too.

I already use plugin.Settings to store persistent plugin data.

But what I would like to do is to store render setting data only for the actual scene (active document).

Like These: (Max bounces, Ray Offset, etc.)

In that case you will want to marry the sample code you mentioned for the UI and the user data on render settings.

The sample code more or less shows global settings (application-wide). You’ll have to come up with a model that uses custom UserData your plug-in knows how to handle. See for user custom user data sample code. Note then that you want to put them on the render settings as custom user data.

I hope this gives you the info you need.

Yes, I think so I can follow this path. (We will see:) Thank you!

It works on the UI part. But how can I make Rhino the update the RenderSettings user data with new UserData? (if possible with undo/redo stack)

I get the userData like tihs:

I change some value…

But how can I store it back to the RenderSettings?


So you use RenderSettings.UserData.Find, then you can use RenderSettings.UserData.Add to set your data.

Thanks you!!!

In case of cameras and objects it was not so simple, so I have forgotten to check this simplest way.

This works great. The only thing is - can it be part of the undo/redo system?

When I do it with a object I put the changes between BeginUndoRecord/EndUndoRecord.

Here it doesn’t work. Do I have to create an own undo step with this? AddCustomUndoEvent(…)

I am not sure if this is part of the undo system.

@andy, @dale - any idea about changing UserData on RenderSettings and undo?

If it is not handled automatically, is it safe to use?: