diff --git a/variables.mk b/variables.mk
index 6917f76..bc1f78c 100644
--- a/variables.mk
+++ b/variables.mk
@@ -3,7 +3,7 @@
 #########################################################################################
 
 #########################################################################################
-# default variables to invoke the generator for a example Rocket system
+# variables to invoke the generator
 # descriptions:
 #   SBT_PROJECT = the SBT project that you should find the classes/packages in
 #   MODEL = the top level module of the project in Chisel (normally the harness)
@@ -18,56 +18,73 @@
 # project specific:
 # 	SUB_PROJECT = use the specific subproject default variables
 #########################################################################################
-SBT_PROJECT       ?= example
-MODEL             ?= RocketTestHarness
-VLOG_MODEL        ?= TestHarness
-MODEL_PACKAGE     ?= $(SBT_PROJECT)
-CONFIG            ?= DefaultRocketConfig
-CONFIG_PACKAGE    ?= $(SBT_PROJECT)
-GENERATOR_PACKAGE ?= $(SBT_PROJECT)
-TB                ?= TestDriver
-TOP               ?= RocketTop
 
 #########################################################################################
 # subproject overrides
 # description:
 #   - make it so that you only change 1 param to change most or all of them!
 #   - mainly intended for quick developer setup for common flags
-#   - for each you only need to specify a CONFIG
 #########################################################################################
 SUB_PROJECT ?= example
 
+ifeq ($(SUB_PROJECT),example)
+	SBT_PROJECT       ?= example
+	MODEL             ?= RocketTestHarness
+	VLOG_MODEL        ?= TestHarness
+	MODEL_PACKAGE     ?= $(SBT_PROJECT)
+	CONFIG            ?= DefaultRocketConfig
+	CONFIG_PACKAGE    ?= $(SBT_PROJECT)
+	GENERATOR_PACKAGE ?= $(SBT_PROJECT)
+	TB                ?= TestDriver
+	TOP               ?= RocketTop
+endif
 # for a BOOM based example system
 ifeq ($(SUB_PROJECT),boomexample)
-	MODEL=BoomTestHarness
-	TOP=BoomTop
+	SBT_PROJECT       ?= example
+	MODEL             ?= BoomTestHarness
+	VLOG_MODEL        ?= TestHarness
+	MODEL_PACKAGE     ?= $(SBT_PROJECT)
+	CONFIG            ?= DefaultBoomConfig
+	CONFIG_PACKAGE    ?= $(SBT_PROJECT)
+	GENERATOR_PACKAGE ?= $(SBT_PROJECT)
+	TB                ?= TestDriver
+	TOP               ?= BoomTop
 endif
 # for BOOM developers
 ifeq ($(SUB_PROJECT),boom)
-	SBT_PROJECT=boom
-	MODEL_PACKAGE=boom.system
-	MODEL=TestHarness
-	CONFIG_PACKAGE=boom.system
-	GENERATOR_PACKAGE=boom.system
-	TOP=ExampleBoomSystem
+	SBT_PROJECT       ?= boom
+	MODEL             ?= TestHarness
+	VLOG_MODEL        ?= TestHarness
+	MODEL_PACKAGE     ?= boom.system
+	CONFIG            ?= BoomConfig
+	CONFIG_PACKAGE    ?= boom.system
+	GENERATOR_PACKAGE ?= boom.system
+	TB                ?= TestDriver
+	TOP               ?= ExampleBoomSystem
 endif
 # for Rocket-chip developers
 ifeq ($(SUB_PROJECT),rocketchip)
-	SBT_PROJECT=rebarrocketchip
-	MODEL_PACKAGE=freechips.rocketchip.system
-	MODEL=TestHarness
-	CONFIG_PACKAGE=freechips.rocketchip.system
-	GENERATOR_PACKAGE=freechips.rocketchip.system
-	TOP=ExampleRocketSystem
+	SBT_PROJECT       ?= rebarrocketchip
+	MODEL             ?= TestHarness
+	VLOG_MODEL        ?= TestHarness
+	MODEL_PACKAGE     ?= freechips.rocketchip.system
+	CONFIG            ?= DefaultConfig
+	CONFIG_PACKAGE    ?= freechips.rocketchip.system
+	GENERATOR_PACKAGE ?= freechips.rocketchip.system
+	TB                ?= TestDriver
+	TOP               ?= ExampleRocketSystem
 endif
 # for Hwacha developers
 ifeq ($(SUB_PROJECT),hwacha)
-	SBT_PROJECT=hwacha
-	MODEL_PACKAGE=freechips.rocketchip.system
-	MODEL=TestHarness
-	CONFIG_PACKAGE=hwacha
-	GENERATOR_PACKAGE=hwacha
-	TOP=ExampleRocketSystem
+	SBT_PROJECT       ?= hwacha
+	MODEL             ?= TestHarness
+	VLOG_MODEL        ?= TestHarness
+	MODEL_PACKAGE     ?= freechips.rocketchip.system
+	CONFIG            ?= HwachaConfig
+	CONFIG_PACKAGE    ?= hwacha
+	GENERATOR_PACKAGE ?= hwacha
+	TB                ?= TestDriver
+	TOP               ?= ExampleRocketSystem
 endif
 
 #########################################################################################
@@ -121,7 +138,7 @@ output_dir=$(sim_dir)/output
 #########################################################################################
 # build output directory for compilation
 #########################################################################################
-build_dir=$(sim_dir)/generated-src
+build_dir=$(sim_dir)/generated-src/$(long_name)
 
 #########################################################################################
 # vsrcs needed to run projects