diff --git a/rtiow/Cargo.lock b/rtiow/Cargo.lock
index 43399f7..fc558ab 100644
--- a/rtiow/Cargo.lock
+++ b/rtiow/Cargo.lock
@@ -2641,6 +2641,7 @@ dependencies = [
  "structopt 0.2.18",
  "strum",
  "strum_macros",
+ "thiserror",
  "vec3",
 ]
 
diff --git a/rtiow/renderer/Cargo.toml b/rtiow/renderer/Cargo.toml
index eeb6c36..cd0e504 100644
--- a/rtiow/renderer/Cargo.toml
+++ b/rtiow/renderer/Cargo.toml
@@ -29,6 +29,7 @@ vec3 = {path = "../vec3"}
 stl = {path = "../../../stl"}
 strum = { version = "0.24.1", features = ["derive"] }
 strum_macros = "0.24.3"
+thiserror = "1.0.38"
 #stl = {git = "https://git-private.z.xinu.tv/wathiede/stl"}
 
 [dev-dependencies]