Didn't get a Planetarium with Crystal Ball?

[Rokk]

The wiki page for Crystal Ball (as well as the ingame descriptions mod) says that Crystal Ball gives you a 100% chance to get a Planetarium if an item room was skipped.

So I picked it up and skipped the item room on that floor (didn't even open it or go into it) and went to the next floor. However, the next floor had no Planetarium. What gives?

[steven]

Check planetarium generation too, not only how to increase chances to have one !
CC CV from the wiki of planetarium :

"Planetariums are very low priority for the game when it generates a level and places rooms, [...] there are reasons one may not be generated even if guaranteed. "

So, planetarium, even with 100% chances to spawn, CAN NOT spawn if other more important structures need to spawn (dice rooms, curse room, gamble room, sacrifice room...).
A floor is limited in number of structures so if the limit is reach by all the more important priority, the game will not generate a planetarium and you will need to wait for the next floor or the next next floor and so on... to have one

[Nazemec]

Originally posted by Rokk:

The wiki page for Crystal Ball (as well as the ingame descriptions mod) says that Crystal Ball gives you a 100% chance to get a Planetarium if an item room was skipped.

So I picked it up and skipped the item room on that floor (didn't even open it or go into it) and went to the next floor. However, the next floor had no Planetarium. What gives?

From the same wiki page:

The Planetarium bonus guarantees the level generation to attempt placing one, but the level layout may not have enough room. Read the article on Planetariums for further details.

[Rokk]

Damn, that sucks. I got literally 0 Planetariums the whole run (I found Crystal Ball on Basement 2). I even got a Dice Room with a forget-me-now effect, still nothing on that "extra" floor.

I guess going for Planetariums on purpose is a losing strategy then?

[steven]

Depend which mark you are doing.

If you go to the beast, you should skip treasures room to have planetarium coz you will have your items back on the ascent to home (quality of planetarium items doesnt matter here, it's additionnal stuff).
If you wanna go somewhere else, it's risky : when you skip one item room, you "loose" one item (sometime good, sometime bad) and you can't claim it back. If you have good stuff, you can skip treasures room but if you struggle to stay alive or kill enemies, better take treasures room and forget about planetarium.

Additionaly, planetariums are not insta win condition : some items are quality of life (mercurius, pluto, sol), some are piece of ♥♥♥♥ (mars, jupiter, neptunus) some are not good but not bad either (saturnus, venus) and some are pretty good (luna, terra, uranus).

Do you want to skip treasure room, depending on your stuff and health, to have sometime a good, decent or a bad item (hello mars and jupiter, the worst) ? The risk/reward is high enough for this run ? Am i going to insta win coz of a gamebreaking combo with planetarium and my items or am i going to loose coz the planetarium was bad af and i don't have many items left to pick ?

[SonicDen220]

Originally posted by Rokk:

Damn, that sucks. I got literally 0 Planetariums the whole run (I found Crystal Ball on Basement 2). I even got a Dice Room with a forget-me-now effect, still nothing on that "extra" floor.

I guess going for Planetariums on purpose is a losing strategy then?

Interesting fact: floor rerolls are actually detrimental for a planetarium chance because it accounts not for treasure rooms skipped, but rather, for floors where you didn't enter a single treasure room. This means that if you skip a treasure room and reroll the floor, you won't get +20% planetarium chance, because it will still be considered the same floor. And if you do enter the treasure room and restart the floor, you will actually get -20% chance (it can't go below 1% though and it will not remove the bonus from other means such as magic 8 ball and telescope lens).
Other things that are detrimental include red key treasure rooms and the mirror world treasure room with knife piece 1.

I really like planetariums and I skip the first item room in most of my runs (and it pays off most of the time, though I get planetariums most frequently in Mausoleum 2), but the formula for their chance is so dumb. I wish the chance couldn't be decreased until you actually enter one.

[mentally stable tf2 gamer]

may be anecdotal, but i've gotten crystal ball numerous times and it's never gotten me a planetarium. Generation is one thing but considering it's supposed to guarantee a planetarium, it just seems like the wiki is wrong about this.

[Rokk]

Yeah I'm a little skeptical too. I've had the other Planetarium chance-increasing items give me a few of them in a run, but I've done two runs with Crystal Ball, skipped an item room both times, and got no Planetarium at all both times.

Not sure what the source for Crystal Ball increasing Planetarium chance to 100% is, but it seems fake. Might have to use that "Planetarium chance" mod to check, assuming it actually reads out the value and doesn't just calculate it itself.

[steven]

Originally posted by Rokk:

Yeah I'm a little skeptical too. I've had the other Planetarium chance-increasing items give me a few of them in a run, but I've done two runs with Crystal Ball, skipped an item room both times, and got no Planetarium at all both times.

Not sure what the source for Crystal Ball increasing Planetarium chance to 100% is, but it seems fake. Might have to use that "Planetarium chance" mod to check, assuming it actually reads out the value and doesn't just calculate it itself.

Again, even mods that tell you 100% chance are wrong (go on reddit or on this forum, you will see numerous ppl crying they didn't have a planetarium with a 100% chance with the mod).
Again, reread my second post.

Crystal ball give you 100% chance to have a planetarium (after skipping a treasure room) but the generation priority of this room is the lower in the game. Higher priority rooms spawns and then it check if there is enough space to spawn lower priority rooms (planetariums for example) or not.

If there is enough space, then the game generate the planetarium according to the probability (100% chance means a planerarium will generate, 20% chance means you can have one, 1% mean it's highly not possible to have one)

THE END

--> 100% CHANCE DOESN'T MEAN PLANETARIUM WILL SPAWN WITH THESE RULES

[wckowalski]

Basically, it generates the basic map layout first before deciding what room is what. Then it checks for all the rules about what rooms spawn (normally guarantees a boss room, secret rooms, shop, and treasure room, some other rooms have chances, possibly based on conditions like having so many coins or keys, some trinkets or items may cause 2 of certain rooms, etc. For most of these (exceptions include the regular secret room which I think is placed after the regular layout and all the decisions about what each room is, and if the boss room is double sized), they have to be single room that is a dead end. Based on a certain priority and rules it then places the rooms it decides you should have. One notable rule is that the boss room is usually the most distant (or possibly tied with another room) from the start, second most distant is second secret room, third is the shop. This is why the second secret room is often close to the boss room, or if not, maybe close to the shop. It also can't generate a floor without enough valid special room locations for those and the treasure room which must necessarily occur (unless on chapter 4 or later or in a challenge that cancels them or something like that)

Now the thing is, after deciding based on the odds if you should have a planetarium (including if it is 100% odds), it first assigns all the other special room types, and if after doing that there aren't any remaining dead end single sized rooms to make into a planetarium, your planetarium is canceled.

Thus, having higher planetarium odds, up to 100%, will increase your chance of a planetarium, but after passing that check, there is a second check based on the floor layout. It's hard to calculate the odds this will fail as it depends on a number of variables, like how later floors have more rooms, and all the things that can change the chances of other not guaranteed special rooms or generate duplicate ones (each extra room reduces the chance of passing this check.

To use an analogy, say you are gambling in a card game, and due to perfect card counting, cheating with marked cards or some other factors, you conclude that based on the rules of the game you are guaranteed to win at the end of the hand once one more last card is dealt. However, then the dealer suddenly has a heart attack and dies or the casino catches fire or something, and that last card never actually gets dealt with the paramedics or police clearing everyone out of the room. Thus you were 100% guaranteed to win yet you didn't due to an entirely separate situation from the rules you were basing that on.

[Rokk]

I understand all that, but I tested it out with the debug console and still got 0 Planetariums in the 3-4 runs I tried. Especially the later floors have more "space" for special rooms to generate, but I still saw 0 of them.

I used the debug console to instead stack trinkets and items that increase the Planetarium chance, and that made a few of them appear.

I think Crystal Ball does not increase the chance to 100%, even if you skip an item room. This was either never a feature, or it is an intended feature that doesn't work correctly.

[LSDBunny]

Originally posted by steven:

Depend which mark you are doing.

If you go to the beast, you should skip treasures room to have planetarium coz you will have your items back on the ascent to home (quality of planetarium items doesnt matter here, it's additionnal stuff).
If you wanna go somewhere else, it's risky : when you skip one item room, you "loose" one item (sometime good, sometime bad) and you can't claim it back. If you have good stuff, you can skip treasures room but if you struggle to stay alive or kill enemies, better take treasures room and forget about planetarium.

Additionaly, planetariums are not insta win condition : some items are quality of life (mercurius, pluto, sol), some are piece of ♥♥♥♥ (mars, jupiter, neptunus) some are not good but not bad either (saturnus, venus) and some are pretty good (luna, terra, uranus).

Do you want to skip treasure room, depending on your stuff and health, to have sometime a good, decent or a bad item (hello mars and jupiter, the worst) ? The risk/reward is high enough for this run ? Am i going to insta win coz of a gamebreaking combo with planetarium and my items or am i going to loose coz the planetarium was bad af and i don't have many items left to pick ?

Also which character. T. Keeper doesnt need treasure rooms, he gets treasure items from shops, which dont need a key for him. Lost can't use many treasure room items, might be a good strategy to avoid treasure rooms with him. T. Bethany has lemegton and can potentially get more use out of planetariums than others.
Also I don't know why people keep saying Jupiter is bad. It gives you +2 health and the fart clouds are an effective AoE attack. Saturnus however actually killed me on a T. Lost run once :/

[HeraldOfOpera]

Originally posted by Bun:

Originally posted by steven:

Depend which mark you are doing.

If you go to the beast, you should skip treasures room to have planetarium coz you will have your items back on the ascent to home (quality of planetarium items doesnt matter here, it's additionnal stuff).
If you wanna go somewhere else, it's risky : when you skip one item room, you "loose" one item (sometime good, sometime bad) and you can't claim it back. If you have good stuff, you can skip treasures room but if you struggle to stay alive or kill enemies, better take treasures room and forget about planetarium.

Additionaly, planetariums are not insta win condition : some items are quality of life (mercurius, pluto, sol), some are piece of ♥♥♥♥ (mars, jupiter, neptunus) some are not good but not bad either (saturnus, venus) and some are pretty good (luna, terra, uranus).

Do you want to skip treasure room, depending on your stuff and health, to have sometime a good, decent or a bad item (hello mars and jupiter, the worst) ? The risk/reward is high enough for this run ? Am i going to insta win coz of a gamebreaking combo with planetarium and my items or am i going to loose coz the planetarium was bad af and i don't have many items left to pick ?

Also which character. T. Keeper doesnt need treasure rooms, he gets treasure items from shops, which dont need a key for him. Lost can't use many treasure room items, might be a good strategy to avoid treasure rooms with him. T. Bethany has lemegton and can potentially get more use out of planetariums than others.
Also I don't know why people keep saying Jupiter is bad. It gives you +2 health and the fart clouds are an effective AoE attack. Saturnus however actually killed me on a T. Lost run once :/

It's not so much that Jupiter is ineffectual, although it's a speed down if you don't take a moment to stand still (which ends up slowing you down anyway). Most of the complaints I've seen are about how annoying the constant fart sounds are.

[LSDBunny]

Originally posted by HeraldOfOpera:

Originally posted by Bun:

Also which character. T. Keeper doesnt need treasure rooms, he gets treasure items from shops, which dont need a key for him. Lost can't use many treasure room items, might be a good strategy to avoid treasure rooms with him. T. Bethany has lemegton and can potentially get more use out of planetariums than others.
Also I don't know why people keep saying Jupiter is bad. It gives you +2 health and the fart clouds are an effective AoE attack. Saturnus however actually killed me on a T. Lost run once :/

It's not so much that Jupiter is ineffectual, although it's a speed down if you don't take a moment to stand still (which ends up slowing you down anyway). Most of the complaints I've seen are about how annoying the constant fart sounds are.

Max speed is however just 2, so speed downs aren't too dramatic usually. Max speed is reached fast. Also I've just looked it up and appearently Jupiter also makes you immune to poison. As for the fart sounds... I don't mind them...

[LSDBunny]

Originally posted by Rokk:

I understand all that, but I tested it out with the debug console and still got 0 Planetariums in the 3-4 runs I tried. Especially the later floors have more "space" for special rooms to generate, but I still saw 0 of them.

I used the debug console to instead stack trinkets and items that increase the Planetarium chance, and that made a few of them appear.

I think Crystal Ball does not increase the chance to 100%, even if you skip an item room. This was either never a feature, or it is an intended feature that doesn't work correctly.

I just tested it out myself and it definitely does guarantee a planatarium spawn. You need to skip the item room one floor after the one you got crystal ball though, so if you give yourself crystal ball on basement 1 and skip the item room in basement 2, it should spawn in caves 1.

[Rokk]

Originally posted by Bun:

I just tested it out myself and it definitely does guarantee a planatarium spawn. You need to skip the item room one floor after the one you got crystal ball though, so if you give yourself crystal ball on basement 1 and skip the item room in basement 2, it should spawn in caves 1.

Oh okay, that actually makes a lot of sense. All my tests were by finding or spawning the crystal ball and then skipping the item room on the same floor.