Father Elijah was searching for the weapon, stating that someone must have scavenged it and sold it on the Strip. Sarah Weintraub mentions that she had it at one point, but sold it to a man wearing a strange collar. Currently, a child named Max is in possession of it, using it as a toy, chasing another child, Stacey, around Freeside with it.
The C-Finder is a handheld rangefinder linked to an orbiting laser weapon, the ARCHIMEDES II. Firing Euclid's C-Finder will result in a five-second delay and an animated sequence on the weapon's display before the impact. Euclid's C-Finder is not influenced by the player character's Energy Weapons skill.
Pressing the trigger constitutes firing the weapon, which will alert nearby enemies. The weapon can only be used once every 24-hours in-game, and does not work indoors. Euclid's C-Finder can fire a total of about 3995 times from full condition before breaking.
In Freeside, outside of Mick & Ralph's, the player character can find Max during the day. The player character can pay Max 1000 bottle caps, or 20 bottle caps with a Barter skill of 45 or more. Otherwise, the player character can wait until Max goes to bed, usually after 9 pm, then pickpocket the weapon from him, resulting in a loss of Karma.
- That Lucky Old Sun: In order to use Euclid's C-Finder, the player character must complete the quest and choose to direct power to ARCHIMEDES II at the end of the quest. If the player has already completed that quest without directing the power to ARCHIMEDES II, the C-Finder cannot be activated.
- Euclid's C-Finder cannot be used in V.A.T.S.
- If one has Veronica as a companion, she will respond "Yeah, I guess it works" when it is first fired.
- The weapon will not always fire if the recharge time of 24 hours is waited using the "wait" function instead of in-game time.
- Sometimes, around every two days, one may obtain another C-finder from Max if the player character chooses to use the Barter check. This can be repeated up to four times.
- Even though Euclid's C-Finder is considered a unique weapon, there is no "normal" variant of it.
- If one pickpockets the weapon from Max instead of buying it, he will later reappear chasing Stacey. He will not have the weapon equipped, but if one talks to him he will pull it out. The player character can then wait until it gets dark and pickpocket another from him.
- After firing it for the first time, Mr. New Vegas will have a news article about the event on Radio New Vegas.
- If the player character did not direct the power to ARCHIMEDES II at the end of That Lucky Old Sun, this can be reverted through the console command set "e282d".nPowerConfiguration to 4.
- Aiming too close to the blast radius will prevent the C-Finder from working, notifying that "You are within the blast radius citizen, move further away."
Behind the scenes
The name Euclid's C-Finder, and the graphics it shows the player while it is operating, are a reference to using Euclidean geometry to find the third point, C, of a triangle, given points A and B, and distances BC and AC. In this example B is the player's position on the ground, A is the position of the ARCHIMEDES II satellite, and C is the position of the target.
- The Courier: "Tell me about the rangefinder."
Veronica Santangelo: "It's a targeting device for some kind of doomsday weapon based at HELIOS One. It was lost sometime after the War. We held HELIOS One for a time. Lost a lot of people defending it. Too many. All for this weapon they never got working. If it turns out to be a dud, it'd show how flawed our goals have been. Father Elijah said he thinks a scavenger might have sold it on the Strip."
(Veronica Santangelo's dialogue)
- The Courier: "I'm looking for an antique rangefinder somebody might've sold you."
Sarah Weintraub: "Wow, I wish I had more of them. All this interest. It'd be my biggest seller. I sold it to a man not too long ago. Real twitchy, nervous sort of guy. Kinda seemed like he was wiggin' out about something. Had a funny collar on. I wanted to ask him about it but I figured maybe I'd regret asking. People are weird around here."
(Sarah Weintraub's dialogue)