Unload inactive scenes
Release CPU and GPU memory after a scene stops cooking. Progressive unloading includes POP buffers and spreads the work across frames.
Cooking and memory ↓TouchDesigner components · Base & Pro
SimpleSceneChanger
Switch scenes. Stop cooking the ones you’re not using. Release their GPU memory.
A .tox component for your TouchDesigner project, with five transition modes, a manual A/B fader and automatic scene playback. Pro adds per-scene settings, cue tables and a CHOP output for scene control data.
Included in Base & Pro
Keep a whole set in one project
Run the scenes you need
Control Cook pauses inactive scene COMPs. The current and incoming scenes keep cooking through the transition.
Let the next scene warm up
Start feedback, particles and movies before the scene appears. Set how many seconds it gets to cook before the switch.
Give the outgoing scene time
Keep it cooking after the switch so an exit animation can finish off-screen. It stops and unloads afterward.
Use your physical fader
Move to the opposite end to switch scenes. Select the next scene and move back. The fader never needs resetting.
How the fader works ↓Let the scenes play
Step through scenes on an interval, in order or in a repeatable shuffle. Auto Advance is included in the Base edition.
Automatic playback ↓GPU memory · Base & Pro
Release VRAM between scenes
Stopping a scene from cooking doesn’t release its GPU memory. Enable Unload to release those resources when the scene is no longer in use.
Progressive unloading, with a frame budget
Unload Budget sets the time in milliseconds spent unloading per frame. Progressive unloading covers every node type, including POP buffers. Immediate mode unloads unlocked TOPs in a single frame. Locked operators are preserved.
Cook control recalculates the active scenes after every change: visible, incoming, pre-rolling and still in Outro. Redirecting a transition won’t leave an abandoned scene cooking indefinitely.
If a scene is selected again before its unload starts, it keeps its memory.
Transitions · Base & Pro
Fade on a timer or switch on cue
Crossfade
Blend to the next scene over Crossfade Length. Choose an Easing curve to shape the transition.
Fade through black
Set separate fade-out and fade-in times. Fade Style chooses black with alpha preserved, or a fade to transparency.
Cut or finish now
Cut switches immediately. Finish Transition completes an active fade, pre-roll or A/B transition when you need to move on.
Change your mind mid-transition
Change Select to restart toward another scene. A timed transition restarts from the fully visible scene, so a redirect can cause a visible snap. Select the current scene to cancel.
Set timing per scene, even in Base
Add Fadeintime, Fadeouttime, Fadeincurve or Fadeoutcurve custom parameters to a scene COMP to override the global times and curves.
A/B fader · Base & Pro
Back and forth, scene after scene
Bind or export your controller’s channel to A/B Fader. Each completed switch makes the opposite end the new starting point.
Choose A/B Fader Crossfade or A/B Fader Through Black. In the latter, the first half fades out and the second half fades in. Easing does not apply.
- Start with the fader at either end: 0 or 1.
- Set Select to the next scene. The current scene stays visible.
- Move to the opposite end to complete the transition.
- Select another scene and move back for the next switch.
- Return to the starting end before completing to cancel. Change Select mid-way to replace the incoming scene.
Auto Advance · Base & Pro
Run through your scenes automatically
Set an Interval and let the component switch scenes for you. The interval includes the transition.
In order or shuffled
Sequential follows Direction and Loop Type: stop at an end, wrap around or ping-pong. Random shows every other scene in a shuffled order before repeating. Use Random Seed to reproduce the sequence.
Turn Auto Advance off to pause the countdown. Choose a scene manually to restart it from that scene. Next Switch In shows the time remaining.
For a show with cue-by-cue timing or an external clock, use Pro’s cue table.
SimpleSceneChanger Pro
Per-scene settings, show cues and control data
All the Base features, plus controls for scenes with different requirements and shows that follow a cue list. Pro is a separate .tox built from the same engine.
Pro · Per-scene settings
Give each scene its own settings
Each Inputs block has Mode In/Out, Fade In/Out, Easing In/Out, Pre-Roll and Outro. Leave menus on Global and times on -1 to inherit the defaults.
Use Always Cook for a scene that other scenes read from. Leave As Is excludes a scene from Control Cook, Unload, Colorize and Active.
Arriving scene
Mode In · Fade In
Easing In · Pre-Roll
Leaving scene
Mode Out · Fade Out
Easing Out · Outro
Mode In wins when both scenes specify a mode. In A/B modes, the fader drives the switch.
Pro · Cue table
Build a show in a Table DAT
Set a scene, duration and transition for each cue. Run on the component’s clock, lock to the timeline, or follow an external CHOP channel or timecode.
Start, stop, pause, change speed, loop, step to the next cue or jump to a cue number. Stop keeps the current scene visible.
Create Table starts from your scenes
One pulse builds a new cue table beside the changer and assigns it to Cue Table. It uses your current scene settings, with one cue per scene. Existing tables are left intact.
The table uses Timer CHOP segments, including delays, cycles and holds. Set cycle to 1 and cyclelimit to 0 to hold a cue until Next Cue.
scene length mode fadein cycleendalert label intro 8 fade 1.5 1 Opening tunnel 12 cross 2 0.5 Build finale 6 cut Drop
Use cycleendalert to start cooking the next scene before its cue. Cue switches follow the table’s timing without waiting for Pre-Roll or the A/B Fader. Auto Advance is disabled whenever Cue Mode is not Off.
Pro · CHOP output
Transition control data with the picture
Blend lighting values, audio-reactive levels or camera controls from scene CHOPs on a second output connector. Choose a CHOP on each Inputs block or use the scene COMP’s Out CHOP.
A/B Fader, Finish Transition, cue switches and Auto Advance also drive the CHOP blend.
Choose how channels are combined
Match by name or index. Missing channels can fade to zero, hold their value or be dropped. For different sample counts, stretch, pad or trim.
Through-black transitions can crossfade channels across the full transition, switch at black, or dip the values to zero with the picture.
Base vs Pro
Choose the controls your project needs
Both editions share the switching engine, cook control and GPU memory unloading.
| Feature | Base | Pro |
|---|---|---|
| Crossfade, Fade Through Black and Cut | Included | Included |
| Both A/B Fader modes | Included | Included |
| Easing, Fade Style and Finish Transition | Included | Included |
| Control Cook, Pre-Roll and Outro | Included | Included |
| GPU memory unloading, including POP buffers | Included | Included |
| Auto Advance with sequential or seeded random order | Included | Included |
| Per-scene times and curves via scene COMP parameters | Included | Included |
| Wiring tools, alignment and node colors | Included | Included |
| Python API, dependable properties and five callbacks | Included | Included |
| Per-scene Inputs settings and cook policies | Not included | Included |
| Cue table, time sync and Create Table | Not included | Included |
| CHOP output and channel/sample matching | Not included | Included |
| onCueEnter and onCueListDone callbacks | Not included | Included |
Setup
Setup and controls
Drag SimpleSceneChanger.tox or SimpleSceneChangerPro.tox into your project. Then connect your scenes and choose how to switch between them.
1 · Wire scenes in
Connect scene COMPs with an Out TOP to the inputs, or reference COMPs or TOPs in the Inputs sequence on the Custom page. For referenced COMPs, the output is the Out TOP, a display-flagged TOP, or the rightmost TOP, in that order. Each input gets a scene index, starting at 0. A bare TOP is displayed but never uncooked or unloaded by the changer.
2 · Pick the scene
Set Select to a scene index or choose a name from Select Menu. You can also use an expression, bind or CHOP export. Loop Type controls how out-of-range indices are handled.
3 · Choose the transition
Choose a crossfade, fade through black, cut or manual A/B transition with Switch Mode. Timed transitions have adjustable duration and Easing. Fade Through Black has separate fade-out and fade-in times.
4 · Decide what cooks
Enable Control Cook to stop inactive scene COMPs from cooking. Pre-Roll starts the next scene before the transition; Outro keeps the previous scene cooking after it. Unload releases memory when a scene stops cooking.
Documentation · Base & Pro
Every parameter, the Python API and callbacks
The full reference lives on its own pages, with each parameter described by its own tooltip from the component.
Base
SimpleSceneChanger Base docs
Switching, the A/B fader, cooking and memory, Auto Advance, and every Base parameter.
Open the Base docs →Pro
SimpleSceneChanger Pro docs
Per-scene settings, the cue table and Cue Mode A/B Fader, CHOP output, and every Pro parameter.
Open the Pro docs →# switch by index or by scene name op('SimpleSceneChanger1').Switch(2) op('SimpleSceneChanger1').Switch('intro', mode='fade') # dependable: expressions follow it on their own op('SimpleSceneChanger1').CurrentName
Connect it to your own system
Switch by index, scene name or operator, step with Next and Previous, and read the visible and incoming scene from dependable properties. Callbacks tell you when a scene starts warming up, starts arriving, gets cancelled or has arrived.