OctaneBlender 2026 Viewport Lag After Saving — Bug Report and Community Fix

[xiecheng0love]

Hello everyone,

Unfortunately, my forum account does not have permission to create a topic in the OctaneRender for Blender section, so I am posting this here and hope it can be forwarded to the Blender development team.

I found a severe performance issue in the OctaneBlender 2026 Add-on. After saving a .blend file, moving objects can become extremely slow. In larger scenes, Blender may become unresponsive and CPU usage can become very high, even when Octane viewport rendering is disabled.

I traced the issue to the Blender dependency graph callback. The add-on was requesting bpy.context.evaluated_depsgraph_get() again inside depsgraph_update_post, even though Blender had already provided the current depsgraph.

Passing the existing depsgraph directly to node_tree_update_handler() completely fixed the lag in my tests.

After the fix:

Saved scenes remain smooth
Large scenes no longer freeze during object transforms
Material, World and light node editing still works normally
Switching between Octane and other render engines also appears more stable

Video demonstration:

[youtube]https://youtu.be/GU557ozTqKc?si=GM_SIx8nH8YABKZz[/youtube]

Unofficial community patch:

https://drive.google.com/file/d/13QVNjX3mpMqrYd8ShowDNcnG3ls44hTS/view?usp=sharing

Tested with:

Blender 5.1.2
OctaneBlender Add-on 31.9
OctaneRender 2026.3
Windows 11
RTX 3090

This is an unofficial fix. Please back up the original add-on files before applying it.

I would appreciate it if a moderator or developer could move or forward this report to the OctaneRender for Blender section.