diff --git a/.github/workflows/CI-full.yml b/.github/workflows/CI-full.yml
index fea6f76e2f..85016d21bc 100644
--- a/.github/workflows/CI-full.yml
+++ b/.github/workflows/CI-full.yml
@@ -181,6 +181,7 @@ jobs:
             needs_maven: true
             needs_secrets: false
             needs_installer_secrets: true
+            needs_vtk_wasm: true
           - name: admin
             dockerfile: docker/build/Dockerfile-admin-dev
             context: .
@@ -233,6 +234,14 @@ jobs:
         sudo tar -xvf deploy/deploy_dir_2025_03_18.tar
         sudo chmod 777 -R deploy
 
+    # The 3D field viewer's wasm bundle is a pinned release asset, not a repo file, and only the
+    # clientgen image ships it. Fetching it here rather than in the maven build keeps a 12 MB
+    # download off every developer's machine for a feature that is disabled by default; developers
+    # who want the viewer locally run the same script themselves (see webapp-viewer/README.md).
+    - name: fetch vtk.wasm bundle for the field viewer
+      if: ${{ matrix.image.needs_vtk_wasm }}
+      run: node webapp-viewer/scripts/fetch-vtk-wasm.mjs
+
     - name: Pre-build step
       if: ${{ matrix.image.pre_build }}
       run: ${{ matrix.image.pre_build }}
diff --git a/docker/build/Dockerfile-clientgen-dev b/docker/build/Dockerfile-clientgen-dev
index b9959ebefe..a66a2be794 100644
--- a/docker/build/Dockerfile-clientgen-dev
+++ b/docker/build/Dockerfile-clientgen-dev
@@ -38,6 +38,20 @@ COPY ./vcell-client/target/vcell-client-0.0.1-SNAPSHOT.jar \
     ./vcell-client/target/maven-jars/*.jar \
     /vcellclient/vcell-client/target/maven-jars/
 
+#
+# The 3D field viewer's web content, served by the client's own loopback field server from
+# <installDir>/webviewer. webapp-viewer has no build step — the source directory is the deployable —
+# so only what the browser actually loads is copied; the fetch script and package.json stay behind.
+#
+# assets/ holds the vtk.wasm bundle, which is gitignored and downloaded by CI before this image is
+# built. If that step did not run, this COPY fails and the image build stops — which is the point:
+# an installer that shipped the page without the bundle would 404 at the moment a user clicks
+# "View in 3D".
+#
+COPY ./webapp-viewer/index.html ./webapp-viewer/viewer.js /vcellclient/webviewer/
+COPY ./webapp-viewer/vendor    /vcellclient/webviewer/vendor
+COPY ./webapp-viewer/assets    /vcellclient/webviewer/assets
+
 COPY ./docker/build/installers /config/
 
 WORKDIR /config
diff --git a/docker/build/installers/VCell.install4j b/docker/build/installers/VCell.install4j
index c6b434517b..4a02eba196 100644
--- a/docker/build/installers/VCell.install4j
+++ b/docker/build/installers/VCell.install4j
@@ -19,6 +19,7 @@
       <variable name="vcellLocalSolversDirPath" value="${compiler:mavenRootDir}/localsolvers" />
       <variable name="vcellLicenseFilePath" value="${compiler:mavenRootDir}/thirdpartylicenses.txt" />
       <variable name="vcellbngPerlPath" value="${compiler:mavenRootDir}/bionetgen" />
+      <variable name="vcellWebViewerPath" value="${compiler:mavenRootDir}/webviewer" />
     </variables>
     <codeSigning macEnabled="true" macPkcs12File="${compiler:macKeystore}" windowsEnabled="true" windowsPkcs12File="${compiler:winKeystore}">
       <macAdditionalBinaries>
@@ -56,6 +57,7 @@
       <mountPoint id="1473" location="resources" />
       <mountPoint id="1474" location="localsolvers" />
       <mountPoint id="1750" location="bionetgen" />
+      <mountPoint id="3200" location="webviewer" />
       <mountPoint id="1348" root="1114" location="nativelibs" />
       <mountPoint id="1349" root="1114" location="nativelibs/mac64" />
       <mountPoint id="1342" root="1114" location="localsolvers" />
@@ -81,6 +83,7 @@
       <dirEntry mountPoint="719" file="${compiler:vcellLibSourcePath}" subDirectory="maven-jars" />
       <fileEntry mountPoint="1473" file="${compiler:vcellLicenseFilePath}" />
       <dirEntry mountPoint="1750" file="${compiler:vcellbngPerlPath}" />
+      <dirEntry mountPoint="3200" file="${compiler:vcellWebViewerPath}" />
       <dirEntry mountPoint="1349" file="${compiler:vcellNativeLibsDirSourcePath}/mac64" />
       <dirEntry mountPoint="1353" file="${compiler:vcellLocalSolversDirPath}/mac64" fileMode="755" overrideFileMode="true" />
       <dirEntry mountPoint="1355" file="${compiler:vcellNativeLibsDirSourcePath}/win64" />
diff --git a/webapp-viewer/scripts/fetch-vtk-wasm.mjs b/webapp-viewer/scripts/fetch-vtk-wasm.mjs
index c4caa7a38c..a635359cba 100644
--- a/webapp-viewer/scripts/fetch-vtk-wasm.mjs
+++ b/webapp-viewer/scripts/fetch-vtk-wasm.mjs
@@ -1,5 +1,5 @@
 #!/usr/bin/env node
-// Build-time fetch of VCell's VTK.wasm bundle into webapp-ng's assets, so the field viewer loads it
+// Build-time fetch of VCell's VTK.wasm bundle into webapp-viewer's assets, so the field viewer loads it
 // SAME-ORIGIN (GitHub release assets can't be fetched cross-origin from the browser — no CORS header).
 // The @kitware/vtk-wasm loader's loadAsync({url}) takes the .tar.gz and untars it in-browser
 // (DecompressionStream + untar), so we serve the .tar.gz as-is. Idempotent. Env: