If you spend much time in Warframe chat, you’re bound to see people trying to organize “radshares” and “intshares.” These are two different types of groups that are formed to run Void Fissure missions. The basic idea behind both is that everyone in the group agrees to run the same Void Relic at the same level of refinement.
Radshare = Radiant Share
In a radshare, all four members of a squad bring a Radiant version of the same Void Relic. This is typically done to increase the chances of getting the rare drop from that relic. For example, a group of people trying to obtain the Titania Prime Systems Blueprint might form a Lith T8 radshare. The published chance of a Radiant relic dropping its rare is 10%. Thus, the chance that at least one of four Radiant relics will drop a rare in a single mission is
1 - (0.9)⁴ ≈ 34.4%
(The value is lower than 40% because there is some overlap: it’s possible that 2, 3, or even all 4 players will roll the rare on the same mission. This “wasted good luck” is the tradeoff for the time-efficiency of opening multiple relics as a group.)
Radiant relics also have the greatest chance to drop uncommon loot, so a radshare can significantly improve the odds of getting the uncommon drop you want. For instance, suppose our squad are now looking to get the Titania Prime Blueprint via a Lith H3 radshare. A single Radiant Lith H3 has a 20% chance of dropping the blueprint (40% of any uncommon drop, divided among the two uncommon drops available). The radshare will provide the Titania Prime Blueprint
1 - (0.8)⁴ ≈ 59.0%
of the time, which again includes cases where 2 or more relics drop the same item.
Notably, it doesn’t matter whether you’re looking for the rare or one of the two uncommons. Radsharing offers you the best per-mission odds of seeing any of those three drops.
Intshare = Intact Share
Likewise, in an intshare, all four squad members bring an Intact copy of the same Void Relic. This is done to maximize the per-mission chances of getting a particular common drop. Intact relics have a 76% chance of dropping any of their three common items, or a 25.33% chance of dropping a specific common item. Thus, if we wanted the Titania Prime Chassis Blueprint, an Axi M2 intshare would give us a
1 - (0.7467)⁴ ≈ 68.9%
chance of seeing it in a given mission.
Flawshares and More
Radshares and intshares are the two most common types of relic sharing groups, but there are also flawshares, in which relics are refined to Flawless instead of all the way to Radiant. This gives a respectable bump to the odds of seeing a rare (22%) and a serious boost to the chances of seeing a given uncommon (each has a nearly 53% chance to show up) while costing half as many Void Traces as a radshare would.
You may also occasionally see flawradshares, in which members are expected to refine their relic to at least Flawless level. These will have rare and uncommon drop rates in between those of a flawshare and a radshare; and the exact rates will depend on how many players refine to Flawless and how many to Radiant.