renderStacks 4.51

4.51 – 8/24/2026

• New – MakePreview pass modifier — makes a viewport preview for the pass. Its controls are the same as the 3ds Max Make Preview dialog; renderStacks adds tokenized output paths, a per-pass preview range and size, and MP4 output. Requires 3ds Max 2024 or newer.
• New – MP4 preview output. Give a MakePreview an .mp4 extension and its frames are encoded with FFmpeg (in the background by default). FFmpeg is auto-detected on first use, or set its path in Preferences → Path Assignment. See the doc for the encode options.
• New – ViewportSettings pass modifier — applies a full set of viewport display settings when the pass is activated. The settings are the same as the 3ds Max viewport configuration; renderStacks adds Capture and per-pass presets. Requires the Nitrous viewport (3ds Max 2020+).
• Improved – Output path length check on the Save modifier. The path preview turns orange at or over the 255-character Windows limit, and Execute warns — listing the passes, with full paths in the Listener — before running an over-limit path.
• Fixed – Action pass modifiers could fire on a simple pass switch (after the Execute menu had been opened) instead of only on Execute.
• Fixed – LayerSet Editor error when shift-clicking a layer with nothing selected (“Unknown property: fullpath in undefined”).