User:Sodabus/Demo Tools Notes

From Valve Developer Community
Jump to: navigation, search


Around the Spring of 2005, I typed out some rather rough notes of how to get around the demo recording tools. I'd forget all of the steps of trying to do any work with the Demo Smoother, and I couldn't find a place that dissected the usage of the Demo Smoother itself, so I compiled a list of directions for some basic camera tasks. As time passed by, I came across several mentions of the Demo Smoother and how the lack of instructions made it difficult to use. At the time, I didn't really have a central place or repository to host my notes, and I had lots of other (real-life) work to do, so I held off my notes for public usage. Now that this Wiki has come about and I actually remembered about my notes (thanks to various queries, Episode One Launch Teaser 4, and the Episode Two trailer), I'm posting them on this page for anyone out there to use.

-- Sodabus

Demo Smoother Notes


  1. Record a demo (While in-game, record filename, record the demo, stop to stop recording)
  2. Load demo (via Shift+F2 or demoui or playdemo filename)
  3. Pause the demo
  4. Push the Smooth... button to enter the Demo Smoother menu
  5. Push the Reload button
  6. Specify a start and end tick range
  7. Push the Select button (Tick range and timespan will appear in the top of the menu.)

The light blue cube is the world origin.
The dark blue cube is the current tick's camera view.
A red cube is a camera view target keyframe.
A green cube is a camera location keyframe.

-/+ Key/Target buttons: last key/target / next key/target

Basic Locational Recam

  1. Enter in the Start Tick value in the Jump To field
  2. Push the Jump To button (If necessary, push the << and >> buttons to ensure that the correct tick is chosen at the top of the menu. This step is critical! Note that you can only use these buttons when the button between them is in Resume mode)
  3. Push the Drive... button on the Demo Playback menu
  4. Drive to the starting location for the new camera path (Hold down the left mouse button and use the WASD keys along with moving the mouse to travel around in the map. This is similar to navigating in a 3D viewport in Hammer)
  5. Adjust the view as to where the beginning of the recam should point at
  6. Push the Make Key button on the Demo Smoother menu. A green cube will appear at the feet (pivot point?) of the player, along with a green line protruding out of the box, pointing at where the (imaginary) crosshairs were centered at
  7. Enter in the End Tick value in the Jump To field
  8. Push the Jump To button (again, making sure that the correct tick is displayed on the top of the menu.)
  9. Drive to the ending location for the new camera path
  10. Push the Make Key button
  11. Push the Process-> button and select Spline Origin (This interpolates the view between the two camera keyframes to match the current player's view during the demo recording (?))
  12. Push the Process-> button again, and select Spline Angles (This locks and blends the camera angles to the ones specified in the two keyframes

To view the new camera path, unselect the Drive... button on the Demo Playback menu and select the Show Processed button on the Demo Smoother menu. Push the Save button when finished. This creates a demo named filename_smooth.dem with the new camera path.

Basic View Recam

  1. Load a demo, open the Smoother, Reload and Select a Start and End Tick range
  2. Jump to the tick within the range where the first target should be
  3. Drive towards the location of the first target
  4. Push the Make Target key. A red cube will appear
  5. Jump to the tick within the range where the last target should be
  6. Drive towards the location of the last target
  7. Push the Make Target key
  8. Push the Process-> key and select Look At Points (this is for a linear interpolation; Process-> Look at Points Spline will create a smoothened out spline)

Wishlist/Things to Find Out

  • A way to "teleport" to a given set of coordinates and view angles while using the demo tools; something similar to the getpos/setpos commands in-game, except ones that would work in the demo tools. This would help in getting a recam to stay locked on an axis or creating better panoramic camera paths.
  • A way to reload all of the target and key cubes and their paths in smoothened and non-smoothened demos after exiting the demo tools. It's hard to do long sequences in one sitting.