diff --git a/Documentation/README.md b/Documentation/README.md
index 9fbea3d..f94e098 100644
--- a/Documentation/README.md
+++ b/Documentation/README.md
@@ -561,6 +561,14 @@ Lines can be used to add markup in 3D. Each line is defined by three dimensional
ClippingPlanes can be used to define a subsection of a building model that is related to the topic. Each clipping plane is defined by Location and Direction. The Direction vector points in the _invisible_ direction meaning the half-space that is clipped.
+### Markers (optional)
+
+A marker is a way to pinpoint a location in the 3D model. Each vendor can decide how these markers should be rendered.
+
+**Best practice**
+Render the markers based on the topic properties.
+Example: Red markers for open topics, and green markers for closed topics
+
### Bitmap (optional)
A list of bitmaps can be used to add more information, for example, text in the visualization. It has the following elements:
diff --git a/Schemas/visinfo.xsd b/Schemas/visinfo.xsd
index caa53ad..a5a3b5d 100644
--- a/Schemas/visinfo.xsd
+++ b/Schemas/visinfo.xsd
@@ -31,6 +31,13 @@
+
+
+
+
+
+
+
@@ -217,6 +224,11 @@
+
+
+
+
+