diff --git a/Pipeline/rules.lua b/Pipeline/rules.lua
index b1ad39ce..a52532b4 100644
--- a/Pipeline/rules.lua
+++ b/Pipeline/rules.lua
@@ -11,6 +11,8 @@
 ---the following benefits:
 ---
 ---* Automatic slash-to-backslash conversion for tool filenames
+---* Emits `mkdir` commands for *all* referenced output directories, not just
+---  the ones that are missing from the current working tree.
 ---
 ---Since Tup forbids writing files from the Tupfile, we have to abuse stdout
 ---to get the transformed rules back into the repo. All rule lines are printed
@@ -18,6 +20,7 @@
 ---batch file inside `build.bat`.
 ---@class Rules
 ---@field private rules Rule[]
+---@field private outdirs table<string, boolean> Set of output directories
 local Rules = {}
 Rules.__index = Rules
 
@@ -25,6 +28,7 @@ function NewRules()
 	---@type Rules
 	local ret = {
 		rules = {},
+		outdirs = {},
 	}
 	return setmetatable(ret, Rules)
 end
@@ -52,6 +56,14 @@ function Rules:insert(inputs, tool, args, outputs)
 	end)
 	args = args:gsub("%%o", table.concat(outs, " "))
 
+	tup_append_assignment(outs, outputs.extra_outputs)
+	for _, output in ipairs(outs) do
+		local dir = output:gsub("/", "\\"):match("(.*)\\")
+		if (dir ~= nil) then
+			self.outdirs[dir] = true
+		end
+	end
+
 	local rule = { inputs = ins, tool = tool, args = args }
 	table.insert(self.rules, rule)
 	return string.format("%s %s", tool, args)
@@ -75,6 +87,15 @@ $ : natively run DOS-based tools. Automatically generated whenever `Tupfile.lua`
 $ : is modified.
 $ @echo off
 ]])
+	local outdirs_sorted = {}
+	for dir in pairs(self.outdirs) do
+		table.insert(outdirs_sorted, dir)
+	end
+	table.sort(outdirs_sorted)
+	for _, dir in pairs(outdirs_sorted) do
+		print(string.format("$ mkdir %s %%STDERR_IGNORE%%", dir))
+	end
+
 	for _, rule in pairs(self.rules) do
 		local cmd = rule.args:gsub("%%f", table.concat(rule.inputs, " "))
 		print(string.format("$ %s %s", rule.tool:gsub("/", "\\"), cmd))
diff --git a/build32b.bat b/build32b.bat
index 0657d146..24f50f9c 100755
--- a/build32b.bat
+++ b/build32b.bat
@@ -26,14 +26,6 @@ call set_errorlevel_to_1.bat
 bcc32 >NUL %STDERR_IGNORE%
 if errorlevel 1 goto no_bcc32
 
-: Neither BCC32 nor TASM32 automatically create nonexisting output
-: directories. Tup would, but not everybody can use it.
-mkdir obj %STDERR_IGNORE%
-mkdir obj\Pipeline %STDERR_IGNORE%
-mkdir bin\Pipeline %STDERR_IGNORE%
-for %%i in (1 2 3 4 5) do mkdir obj\th0%%i %STDERR_IGNORE%
-for %%i in (1 2 3 4 5) do mkdir bin\th0%%i %STDERR_IGNORE%
-
 : Regular Tup would return 1 when hitting Ctrl-C, so let's use the immediately
 : returning `version` subcommand to figure out whether we should fall back.
 bin\tup version >NUL
diff --git a/build_dumb.bat b/build_dumb.bat
index 10d33103..1afb4022 100644
--- a/build_dumb.bat
+++ b/build_dumb.bat
@@ -2,6 +2,20 @@
 : natively run DOS-based tools. Automatically generated whenever `Tupfile.lua`
 : is modified.
 @echo off
+mkdir Research %STDERR_IGNORE%
+mkdir bin\Pipeline %STDERR_IGNORE%
+mkdir obj %STDERR_IGNORE%
+mkdir obj\Pipeline %STDERR_IGNORE%
+mkdir obj\th01 %STDERR_IGNORE%
+mkdir obj\th02 %STDERR_IGNORE%
+mkdir obj\th03 %STDERR_IGNORE%
+mkdir obj\th04 %STDERR_IGNORE%
+mkdir obj\th05 %STDERR_IGNORE%
+mkdir th01\sprites %STDERR_IGNORE%
+mkdir th02\sprites %STDERR_IGNORE%
+mkdir th03\sprites %STDERR_IGNORE%
+mkdir th04\sprites %STDERR_IGNORE%
+mkdir th05\sprites %STDERR_IGNORE%
 bcc32 -w-8004 -w-8012 -O2 -v- -x- -nbin/Pipeline/ Pipeline/bmp2arr.c Pipeline/bmp2arrl.c
 tasm32 /m /mx /kh32768 /t Pipeline\zun_stub.asm obj\Pipeline\zun_stub.obj
 tasm32 /m /mx /kh32768 /t Pipeline\cstmstub.asm obj\Pipeline\cstmstub.obj