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diff --git a/topics/02_passive/index.md b/topics/02_passive/index.md
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--- a/topics/02_passive/index.md
+++ b/topics/02_passive/index.md
@@ -38,675 +38,7 @@ Photogrammetry is the collection and organization of reliable information about
 <p>Photogrammetry is useful for outdoors settings, where all you need is a handheld camera and some patience. In this example, note the loss of quality towards the top, as pixel resolution becomes problematic:</p>
 
 
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+<div class="sketchfab-embed-wrapper"> <iframe title="Arc de Triomphe - photogrammetry" frameborder="0" allowfullscreen="" mozallowfullscreen="true" webkitallowfullscreen="true" allow="fullscreen; autoplay; vr" xr-spatial-tracking="" execution-while-out-of-viewport="" execution-while-not-rendered="" web-share="" src="https://sketchfab.com/models/65937fd27de647c0a8ac99ce8275c03e/embed"> </iframe> <p style="font-size: 13px; font-weight: normal; margin: 5px; color: #4A4A4A;"> <a href="https://sketchfab.com/3d-models/arc-de-triomphe-photogrammetry-65937fd27de647c0a8ac99ce8275c03e?utm_medium=embed&amp;utm_campaign=share-popup&amp;utm_content=65937fd27de647c0a8ac99ce8275c03e" target="_blank" style="font-weight: bold; color: #1CAAD9;"> Arc de Triomphe - photogrammetry </a> by <a href="https://sketchfab.com/nicolasdiolez?utm_medium=embed&amp;utm_campaign=share-popup&amp;utm_content=65937fd27de647c0a8ac99ce8275c03e" target="_blank" style="font-weight: bold; color: #1CAAD9;"> Nicolas Diolez </a> on <a href="https://sketchfab.com?utm_medium=embed&amp;utm_campaign=share-popup&amp;utm_content=65937fd27de647c0a8ac99ce8275c03e" target="_blank" style="font-weight: bold; color: #1CAAD9;">Sketchfab</a></p></div>
 
 
 # Key Benefits
@@ -715,12 +47,15 @@ Photogrammetry is the collection and organization of reliable information about
 <p>Affordability and flexibility. Depending on the end use application almost any camera will work given there is enough light and your post processing software is robust.</p>
 <p>Real time feedback and processing as models improve. <a href="https://mars.nasa.gov/technology/helicopter/#">Ingenuity Drone</a></p>
 
-<p><img src="img/lidar-vs-photogrammetry-drone.jpg" alt="Drone imaging"></p>
+<p><img src="img/lidar_vs_photogrammetry_drone.jpg" alt="Drone imaging"></p>
 
 # Key Challenges
+Precision is improving but can still be completely thrown off by certain light conditions in much the same way LiDar struggles with smooth surfaces.
 
+Increasingly industry pairs vision systems for photogrammetry with laser systems to balance the benefits of both.
 # Tools
-
+<p><a href="https://www.autodesk.com/products/recap/overview?term=1-YEAR">Autodesk ReCap</a></p>
+<p><a href="https://www.agisoft.com">Agisoft Metashape</a></p>
 # Apps
 
 # Camera Equations