Essence hole

Essence hole is a mechanic introduced in v1.1.2, based on the Shadowrun 3 core rulebook.

Essence lost due to installing cyberware is not refunded when cyberware is removed or upgraded, but instead creates a "hole", equivalent to the number of essence points removed. When cyberware is swapped out, the game will use points from the hole, rather than the remaining essence.

Previously, any essence points in the hole were lost when (a) it was not re-filled in the same surgery session or (b) cyberware vanished due to different cyberware content packs between UGCs. This made playing street samurais really hard.

Editor and Essence
Currently (2014-01, v1.1.1), neither "Essence" nor "Magic Essence" attribute values can be set via trigger in the editor. Trying to do so will just swallow the action, and any subsequent actions (e.g. a speech bubble) from the same trigger will be ignored. Setting "Magic" attribute value is possible. Some users have tried installing cyberware with negative essence cost, but to no avail. It seems like the source code is something like "function setEssence(actor, newValue) { actor.essence = min(actor.essence, newValue) }".

With v1.1.1 and prior, the "lost essence" problem popped up on the internet in different places [|(1)] [|(2)] [|(3)] [|(4)] [|(5)] [|(6)], but nobody seemed to be able to find a good solution (outside "rebuild the character using some UGC mod"). It is rumored that essence can only be set in the cyberware install screen, and there only decreased.

Harebrained Studios have responded on 2014-01-25, thanks Jeff! The official position sounds very much like the Essence Hole principle of SR3. The following test case was done 2014-01-29 with version 1.1.2 from Steam (using DMS scene "The Estate", buying cyberware from Quoth):
 * 1) install basic cyberarm and basic dermal plating. costs each 1.5 essence, correctly 3 is left. leave menu.
 * 2) install alpha dermal plating. costs 1.0 essence and replaces basic dermal plating. now 3 (3.5) essence is left. leave menu.
 * 3) install alpha cyber eyes. costs 0.5 essence and should fill up the essence hole. however erroneusly, essence 2 (2.5) is shown (instead of the expected 3 (3)). leave menu.
 * 4) however, when viewing character stats (key C), the essence is correctly at 3.

So the only error remaining is the incorrect display in the cyberware install screen, which is only a minor issue. Thanks HBS!

Other Open Questions
Essence and Magic Essence are int values; it is unclear how the fractional value displayed in parentheses in the cyberware install screen is saved.

Official Position
"All actors start with 6 Essence, then when Cyberware is installed the Essence cost is deducted from the characters Essence permanently.

Essence is rounded down in magic calculations only.

If you upgrade to different cyberware that costs less, you do not get the original essence back. Instead, the difference creates an Essence "buffer" and is deducted when additional Cyberware is installed until it is depleted.

Here's an example of Cyberware installation and upgrading, with the help of Street Samurai Bob.

Bob starts out with 6 Essence, he then installs Cybereyes that have an Essence cost of 0.5.

Bob now has 5.5 Essence (this means that Bob only uses 5 Essence for magic calculations), he then installs Dermal Plating with an Essence cost of 2.

Bob now has 3.5 Essence, he then upgrades to Dermal Plating Alphaware with an Essence cost of 1.

Bob still has 3.5 Essence (with a 1 Essence buffer), he then installs a Cyberarm with an Essence cost of 1.

Bob still has 3.5 Essence (the Essence buffer is filled without changing Bob's Essence).

You can see that Essence never is gained once lost, but is allowed to be filled with Cyberware even after upgrading to a lower cost."

- HBS_Jeff on 2014-01-25