Furnace minecarts lose power after navigating corners

Confirmed for 14w31a

Confirmed for 14w34b

There are still problems with how powered minecarts go around corners. If there are two corners, the powered minecart will go about 8-10 blocks then stop. Sometimes they keep going, and rarely they bounce back an go the wrong way before stopping.

Also, powered minecarts no longer push minecarts with chests when both are adjacent and started from a dead stop.

I'll attach some screenshots of the experiments I made. At first I thought the distance between corners made a difference, but after looking at the results I'm not sure.

Haven't you seen any problems when the furnace minecart is running on a straight track? That is what happens to me.
Version 1.8-pre2

There are also other reports marked as duplicate of this, but they don't mention corners.
MC-51103

Confirmed for 1.8 Release.

Powered minecarts seem to work on straight lines now, but after they hit a curve they will stop moving a few blocks away.

Confirmed 1.8/Linux

also happens occasionally on detector rails

An explanation of why this happens:

When a player right-clicks the furnace cart, it is given a push vector based on where the player is stood relative to the cart. In versions prior to 1.8, this vector would be updated every gametick to face in the direction that the minecart is moving - however in 1.8, the push vector is stuck in the direction that the player initially set it to.

If the angle between the push and motion vectors is over 90 degrees (i.e. scalar product is negative), the push vector is set to 0 and the cart will come to a halt.

For example, if you are facing South-West when you right-click the cart, it won't lose power on tracks which take it South or West, and there can be many corners alternating between those two directions.

So.. Can't anyone fix this? Its been quite awhile and as far as I can see, it just kills furnace powered mine carts.

Is it possible to have this issue reviewed? As jim lee said, it kills powered minecarts and makes them useless in the game.

There are thousands of unresolved bugs, Mojang will get to this one eventually. If they go ahead and add in the new minecart mechanics that they had in 14w11a, I'm sure this will be fixed then.

Issac, those "minecart mechanics" (a.k.a Jeb's Minecart Law) were removed by popular demand by the community, so as long as those mechanics stay removed, this is most likely unfixable.

Oh, they were? I didn't realise. That doesn't make this unfixable though, I was just saying that if they ever did something with minecarts, they would probably get to this too, as it also affects minecarts.

What? Powered mine carts were deleted by popular demand?!

@Sonic: this bug is currently making powered minecarts unusable, i would say that this should be high priority...
As for being unfixable, they said that they would "revert" minicarft mechanics, and they did so but they forgot to "revert" ( aka. fix) powered minecarts too

Is no one trying to use Furnace powered mine carts anymore? I have an entire world going back to using horses 'cause the rail system that connects everything won't run anymore.

Is there any way to get this looked at?

thanks!

@jim lee

There are over 3000 unresolved bugs, many of which have been around much longer than this one. Just wait. This will be looked at eventually.

Wait?! Its been a YEAR!

-jim lee

Confirmed and still existing in 1.8.3

--- src/main/java/net/minecraft/server/EntityMinecartFurnace.java	2015-04-06 18:50:46.198347410 +0100
+++ src/main/java/net/minecraft/server/EntityMinecartFurnace.java	2015-04-06 18:50:46.214347410 +0100
@@ -58,17 +58,9 @@
 
         if (d0 > 1.0E-4D && this.motX * this.motX + this.motZ * this.motZ > 0.001D) {
             d0 = (double) MathHelper.sqrt(d0);
-            this.a /= d0;
-            this.b /= d0;
-            if (this.a * this.motX + this.b * this.motZ < 0.0D) {
-                this.a = 0.0D;
-                this.b = 0.0D;
-            } else {
-                double d1 = d0 / this.m();
-
-                this.a *= d1;
-                this.b *= d1;
-            }
+            double d1 = (double) MathHelper.sqrt(this.motX * this.motX + this.motZ * this.motZ);
+            this.a = (motX / d1) * d0;
+            this.b = (motZ / d1) * d0;
         }
 
     }

Full source here: https://gist.github.com/thinkofname/1435c96a8d7efcd2698e

From my testing this seems to completely fix the issue although it might need some more testing

I've made an observation, which thus far has been consistent.

When the Furnace Minecart takes the turn, the orientation of the cart and/or furnace reverses.

1st example:
Cart is rolling with fire to the rear.
Cart transitions turn and fire remains to the rear, the cart continues rolling unabated.

2nd example (converse):
Cart is rolling with fire to the rear.
Cart transitions turn and the fire side flips to the frontward end, the cart stops rolling.

This holds true regardless to directional orientation of the cart (fire to the front side or to the trailing end of forward motion).
So long as the cart/furnace facing remains consistent through and after the turn, the cart continues rolling.
If it reverses, it stops.
There seems to be no rhyme or reason to when it happens. I've witnessed several consecutive turns where the flip did not occur.

I hope this helps. I look forward to the resolve.

Standing at the station waiting for a train that never comes.

Thinkofdeath, how does one apply the script you have posted, and does it address the issue as I have it described?

Should do, don't have it applied to test. The patch itself was applied against Spigot (Minecraft server mod) on the partially de-obfuscated source. Wouldn't recommend trying to apply it yourself unless you understand how to work with the mod, I just included it to show roughly to mojang were I fixed it.

Confirmed 1.8.7/Mac. Definitely looks like the push vector is stuck as described by @unknown.
Observations with a 12x12 loop of track:

• furnace cart started at southwest corner while facing northeast comes to rest at northwest corner (about 10 blocks from northeast corner where its motion vector presumably gets set to 0)

• furnace cart started at southwest corner while facing southeast comes to rest at northeast corner (about 10 blocks from southeast corner where its motion vector presumably gets set to 0)

Relates to:

• MC-53992

• MC-88038

Confirmed for

• 15w36c The problem seems to be with PushX and PushZ. These are the as you called them vectors that determine the Motion of a MinecartFurnace (see comment on MC-88038). However these values are most of the time set to 0 when a MinecartFurnace navigates through a corner. This normally only happens when Fuel is 0, however for corners it does not matter.

The solution has already been fixed by ThinkofDeath just Mojang still has refused to implement it.. I mean unless we trying to get quasi-real physics working, the velocity should never go to zero on a turn regardless it should change the thrust vector to the new direction of travel. It is a powered minecart with a fixed force of thrust. This isnt a simulator so dont see why implementing code that fixes the problem still has not been implemented.

still an issue 15w37a and 15w38a

I'm currently trying to fix up the furnace minecart for my mod Vintagecraft - I can confirm from simple tests that Thinkofdeaths solution fixes the problem of coal powered carts slowing down after going through a curve.

In that regard, thanks for the fix Thinkofdeath!

Mods could you please add the suggested fix to the description?

it is not a suggested fix unless you know what you doing because obfuscation changes in every version release.. best bet is use the 3rd party server or get alot of people to start upvoting this issue so they might finally implement it. if MCP was kept up to date then this would be possible but since it hasnt been updated since 1.8 it would not be recommended.

still an issue 15w39a
... and 15w39b
... and 15w39c

still an issue 15w40a
... and 15w40b

Still an issue in 15w41b

Still an issue in 15w42a

Still an issue in 15w43b

Still an issue in 15w43c

Still an issue in 15w44a

Still an issue in 15w44b

Still an issue in 15w45a

Still an issue in 15w46a

please repair this feature @Mojang! Very important for mechanism: http://minecraft-de.gamepedia.com/Schienenverkehrsanlagen

still an issue in 15w47a

Mojang please check this video: https://www.youtube.com/watch?v=YVGFJRwSe2A.

Problem 2 shows the bug. Problem 3 is the actual trick that players can workaround this bug today.

Problem 2 also does not occurs in 1.7.10 version.

or they could just have implemented the code that fixed the problem provided by one of 3rd party server devs which in fact was implemented and been fixed in said 3rd party server for over half a year now. 😞

still an issue in 15w47b

still an issue in 15w47c

Still an issue in 15w49a

Still an issue in 15w49b

In my Opinion it would be really useful if powered minecarts were given a menue with a coal slot and buttons to define the direction of driving.
And its currently still being an issue in Minecraft 1.8.8

Still an issue in 15w50a and 1.8.9

still an issue in 15w51b

still an issue in 16w02a

still an issue in 16w03a

Console edition also has the same bug (after TU31)

https://bugs.mojang.com/browse/MCCE-1599

still an issue in 16w06a

Please link to @unknown's comment as his github page does not exist anymore

Jeb's opinion about the issue: https://twitter.com/jeb_/status/699241247391772672

"I think we will phase out the furnace minecraft"

Bad news for us, maybe. It needs being reworked, not removed! 😞

Well, crap. That's one way to fix all the furnace minecart mechanics bugs, I guess. =/

Phase out the furnace?

They should at least make the power rails more cheap

MCCE-1599 was marked as "Works As Intended". Should this issue also be marked as "Works As Intended"?

PS: still an issue in 1.9

Funny. But most probably that's now WaI. But Furnace Minecarts will be removed from the game.

Will there be something created to replace them?

This isn't a descussion forum, that's why there is minecraft forum. Also yes this has been confirmed in 1.9.2 and 1.9.1

Confirmed in 16w15b

Still happens in 1.9.4

Confirmed in 1.10

I confirmed that this is still a bug in 1.11. Attached new screenshots

Affects 1.13-pre4

Affects 1.13-pre7

Affects 18w31a

Still an issue in snapshot 18w48b.

Please can this be fixed soon, it's been an issue since 1.8 which puts me off using the newer versions since furnace carts were one of my favorite items in the game.

Confirmed for 19w13b.

Confirmed for 1.14 Pre-Release 4.

If Dinnerbone or Mojang indeed plans to remove furnace minecarts, I suggest just marking this issue as "wontfix" instead of letting a ton of people waiting for this issue be fixed one day.

Nobody at Mojang ever confirmed that furnace minecarts will be removed for sure, they only thought about it, but no decision has been taken as far as I know. Nevertheless, even if the furnace minecart was to be removed from the game, it still is part of the game until it is actually removed.

Confirmed for 1.14.4, still not fixed.

Still an issue on 19w42a, I'm practically begging you at this point to fix this since it has been an issue for nearly five years and I literally stopped playing vanilla minecraft versions because of this as furnace carts were my favourite item.

Please, if you have no intention on fixing this just do what liach said and save me, plus others, the pain by marking it as wontfix because at the moment I still have my hopes up that this will one day be fixed.

Confirmed in 19w46a. Also thanks for adding a mojang priority.

Affects 1.15 pre release 1.