diff --git a/install.ps1 b/install.ps1
index ed468f8..34885af 100644
--- a/install.ps1
+++ b/install.ps1
@@ -36,7 +36,7 @@ $Org            = 'resq-software'
 $NixInstallUrl  = 'https://install.determinate.systems/nix'
 
 # Canonical repo list — keep in sync with install.sh and README.md.
-$ValidRepos = @('programs','dotnet-sdk','pypi','crates','npm','vcpkg','landing','docs')
+$ValidRepos = @('programs','dotnet-sdk','pypi','crates','npm','vcpkg','landing','docs','viz')
 
 # ── Platform flag ────────────────────────────────────────────────────────────
 
@@ -260,8 +260,9 @@ function Select-Repo {
     Write-Host '  ' -NoNewline; Write-Host ' 6' -ForegroundColor Cyan -NoNewline; Write-Host '  vcpkg         C++ libraries'
     Write-Host '  ' -NoNewline; Write-Host ' 7' -ForegroundColor Cyan -NoNewline; Write-Host '  landing       Marketing site'
     Write-Host '  ' -NoNewline; Write-Host ' 8' -ForegroundColor Cyan -NoNewline; Write-Host '  docs          Documentation site'
+    Write-Host '  ' -NoNewline; Write-Host ' 9' -ForegroundColor Cyan -NoNewline; Write-Host '  viz           3D visualization (Three.js/Cesium + Unity)'
     Write-Host ''
-    $choice = Read-Host '  Choice [1-8]'
+    $choice = Read-Host '  Choice [1-9]'
 
     $script:Repo = switch ($choice) {
         '1' { 'programs' }
@@ -272,6 +273,7 @@ function Select-Repo {
         '6' { 'vcpkg' }
         '7' { 'landing' }
         '8' { 'docs' }
+        '9' { 'viz' }
         default { Write-Fail "Invalid choice: $choice" }
     }
 }
@@ -541,6 +543,14 @@ function Show-RepoInfo {
             Write-Host '    npx mint dev for local preview'
             Write-Host ''
         }
+        'viz' {
+            Write-Host ''
+            Write-Host '  What''s included:' -ForegroundColor White
+            Write-Host ''
+            Write-Host '    Three.js / Cesium web viewers (TypeScript)'
+            Write-Host '    Unity 3D viewer (.NET 9, ResQ.Viz.sln)'
+            Write-Host ''
+        }
     }
 }
 
diff --git a/install.sh b/install.sh
index 4da87b7..034008a 100755
--- a/install.sh
+++ b/install.sh
@@ -57,7 +57,7 @@ NIX_INSTALL_URL="https://install.determinate.systems/nix"
 ORG="resq-software"
 
 # Canonical repo list — keep in sync with install.ps1 and README.md.
-VALID_REPOS="programs dotnet-sdk pypi crates npm vcpkg landing docs"
+VALID_REPOS="programs dotnet-sdk pypi crates npm vcpkg landing docs viz"
 
 # ── Utility functions (all log to stderr) ────────────────────────────────────
 
@@ -280,7 +280,8 @@ choose_repo() {
   printf "  ${CYAN} 6${RESET}  vcpkg         C++ libraries\n" >&2
   printf "  ${CYAN} 7${RESET}  landing       Marketing site\n" >&2
   printf "  ${CYAN} 8${RESET}  docs          Documentation site\n" >&2
-  printf "\n  Choice [1-8]: " >&2
+  printf "  ${CYAN} 9${RESET}  viz           3D visualization (Three.js/Cesium + Unity)\n" >&2
+  printf "\n  Choice [1-9]: " >&2
   read -r choice < /dev/tty
 
   case "$choice" in
@@ -292,6 +293,7 @@ choose_repo() {
     6)  REPO="vcpkg" ;;
     7)  REPO="landing" ;;
     8)  REPO="docs" ;;
+    9)  REPO="viz" ;;
     *)  fail "Invalid choice: $choice" ;;
   esac
 }
@@ -503,6 +505,11 @@ print_repo_info() {
       printf "    Mintlify docs site\n" >&2
       printf "    npx mint dev for local preview\n\n" >&2
       ;;
+    viz)
+      printf "\n  ${BOLD}What's included:${RESET}\n\n" >&2
+      printf "    Three.js / Cesium web viewers (TypeScript)\n" >&2
+      printf "    Unity 3D viewer (.NET 9, ResQ.Viz.sln)\n\n" >&2
+      ;;
   esac
 }