Exercise 6: A glow that pulses in place

Purpose. To make one object pulse where it stands, with no particles leaving it.

Every effect so far has been a crowd: many short-lived particles, each a duplicate. Some effects are a single thing that stays put and changes: a crystal that throbs, a warning lamp, a portal that breathes. For those, the emitter can play its graphs on one object in place. This is Animate mode.

Before starting

• The workspace holds one new Part with Shape Ball, Size 2, 2, 2 and Material Neon. Set these in Studio’s own Properties window.

Procedure

Steps 1 and 4 to 6 repeat earlier exercises.

Step	Control	Action	Result
1	The Part	Select, then press Transform	The Part turns invisible. The HUD and the Properties panel open.
2	Properties ▸ Emission ▸ Mode	Set to Animate	The Enabled and Rate rows leave the panel and a Loop row takes their place. The Emit box leaves the HUD.
3	Properties ▸ Emission ▸ Loop	Switch on	The ball appears where the Part is and stays there. Nothing about it changes yet.
4	Properties ▸ Appearance ▸ Size ▸ X, Y, Z	Click each until all three are lit, then press ⋯	The graph editor opens with a level line at 2.
5	Graph editor	Click the middle of the graph area to add a keypoint. Double-click it and enter 3 for Value.	The line rises from 2 to 3 and falls back to 2.
6	Graph editor ▸ Apply	Press	From the next cycle, the ball swells to 3 studs and shrinks back to 2, once a second, without end.
7	Properties ▸ Emission ▸ Lifetime	Enter 2	From the next cycle, one swell takes two seconds.
8	Properties ▸ Emission ▸ Loop	Switch off	The cycle in progress plays to its end. The ball then disappears.
9	HUD ▸ Emit button	Press	The ball appears, plays one cycle, and disappears.
10	Properties ▸ Emission ▸ Linger	Enter 1	No change yet.
11	HUD ▸ Emit button	Press	The ball plays one cycle, holds its last frame for one second, and disappears.

NOTE

In Animate mode an edit shows at the start of the next cycle. The cycle in progress keeps the values it started with.

CAUTION

Changing Mode stops the emitter at once. Particles in flight are removed, and Enabled and Loop are switched off.

CAUTION

A flipbook from the Inventory does not play on a Part emitter in Animate mode. Use Emit mode for flipbooks.

What the steps did

Mode chooses between the two ways an emitter can work.

	Emit	Animate
What is shown	Many duplicates of the template	The template itself, in place
What a graph spans	The life of one particle	One cycle
Lifetime	How long each particle lasts	How long one cycle lasts
Started by	Enabled, for a stream. Emit, for a burst.	Loop, for cycles without end. Emit, for one cycle.
Rate and the Emit box	Used	Not used, and hidden

In Animate mode nothing is duplicated. The object that pulses is the RenderTemplate inside the emitter, made visible for as long as the cycle runs.

Loop repeats the cycle until it is switched off. It is saved with the place: an emitter left looping starts looping again when the place is next opened with the plugin running.

Linger is a hold at the end. After the last frame of a single cycle, the object stays as it is for that many seconds before it disappears. It has no effect between the cycles of a loop.

The switch on the HUD works here too. For an emitter in Animate mode it turns Loop on and off.

If the result differs

Symptom	Cause	Action
No Loop row	Mode is still Emit.	Repeat step 2.
The ball does not change size	The graph was closed with Cancel, or the keypoint was left at 2.	Repeat steps 4 to 6.
The ball jumps from large to small at the end of each cycle	The first and last keypoints differ, so the end of one cycle does not match the start of the next.	Give the first and last keypoints the same Value.
An edit seems to do nothing	The cycle in progress has not finished.	Wait for the next cycle.

Variations

Change	Result
Transparency graph: 0.6, then 0 in the middle, then 0.6	The ball brightens as it swells and dims as it shrinks.
A Color graph whose first and last markers match	The colour shifts through the cycle and returns, with no jump.
Lifetime 0.3	A fast flicker.
Lifetime 1.5, 3	Each cycle takes a length of its own between 1.5 and 3 seconds, so the pulse is uneven.
HUD ▸ Duration 5, then Emit	The cycle repeats for five seconds and then stops by itself.

Log

New in this exercise	Mode. Loop. Linger.
Done before	Transform (Exercises 1, 4 and 5). A Size graph with X, Y and Z lit (Exercise 4). Lifetime (Exercise 2). The Emit button (Exercise 3).
Carried forward	Keep this emitter. Exercise 10 uses it again.