fix cubetree init crash.

App/wwwroot/HiAPI-docsite/api/Hi.Geom.html

@@ -130,7 +130,7 @@ The data contains in a <a class="xref" href="Hi.Geom.Box3d.html">Box3d</a> is <a
     </dl>
     <dl class="jumplist">
       <dt><a class="xref" href="Hi.Geom.Cylindroid.html">Cylindroid</a></dt>
-      <dd><p>Geometry of Cylindroid.</p>
+      <dd><p>3d Geometry of Cylindroid.</p>
 </dd>
     </dl>
     <dl class="jumplist">
@@ -251,11 +251,6 @@ This class combines a transformer with a target geometry to produce transformed
       <dt><a class="xref" href="Hi.Geom.Tri3dUtil.html">Tri3dUtil</a></dt>
       <dd><p>Utility of <a class="xref" href="Hi.Geom.Tri3d.html">Tri3d</a>.
 Include generator of triangles from points.</p>
-</dd>
-    </dl>
-    <dl class="jumplist">
-      <dt><a class="xref" href="Hi.Geom.UnnullableDVec3d.html">UnnullableDVec3d</a></dt>
-      <dd><p>For Unnullable IO for <a class="xref" href="Hi.Geom.DVec3d.html">DVec3d</a>.</p>
 </dd>
     </dl>
     <dl class="jumplist">
@@ -271,6 +266,14 @@ Include generator of triangles from points.</p>
     <dl class="jumplist">
       <dt><a class="xref" href="Hi.Geom.Vec3d.html">Vec3d</a></dt>
       <dd><p>Basic 3D point (or vector).</p>
+</dd>
+    </dl>
+    <h3 id="structs">
+Structs
+</h3>
+    <dl class="jumplist">
+      <dt><a class="xref" href="Hi.Geom.Fraction-1.html">Fraction&lt;TEva&gt;</a></dt>
+      <dd><p>Pure C# unlimited precision fraction.</p>
 </dd>
     </dl>
     <h3 id="interfaces">
@@ -346,7 +349,8 @@ Enums
     </dl>
     <dl class="jumplist">
       <dt><a class="xref" href="Hi.Geom.FractionStatus.html">FractionStatus</a></dt>
-      <dd><p>Status flags for <a class="xref" href="Hi.Geom.NativeFraction.html">NativeFraction</a>.</p>
+      <dd><p>Status flags for Fraction and <a class="xref" href="Hi.Geom.NativeFraction.html">NativeFraction</a>.
+Corresponds to IS_PACKED_MASK and IS_EVALUATED_MASK in C++ fraction_base_t.</p>
 </dd>
     </dl>
     <dl class="jumplist">