fix download .3d file

templates/cave.html

@@ -480,17 +480,22 @@ div#scene {
 
 
 <div id="Description">
-
+{% comment %} The 'cave' object has text field, not forign-key fields, so we cant dereference to get info on the survex file 
+{% endcomment %}
 <p>{% if cave.explorers %}
     <h2>Explorers</h2>
     {{ cave.explorers|safe }}
 {% endif %}
     <h2>Survex File(s)</h2>
-    All <a href="/survexfile/{{cave.kataster_number}}">survexfiles</a> for this cave<br />
+    All <a href="/survexfile/{{cave.kataster_number}}">survexfiles</a> for this cave  {<br />
 {% if cave.survex_file %}
     Primary <a href="/survexfile/{{cave.survex_file}}">survex file</a> for this cave 
     <p>[<a href="https://aardgoose.github.io/CaveView.js/">CaveView</a> display of the .3d file is temporarily disabled while we fix things (Nov.2021).<br> See <a href="/handbook/computing/todo.rst">/handbook/computing/todo.rst</a>.]<br><br>
     
+    Download .3d file <a href="/cave/3d/{{cave}}">caves-{{  cave.area.all.0.kat_area }}/{{cave.kataster_number}}/{{svx3d}}.3d</a>
+<br>
+cave ID '{{cave.reference}}'<br>
+cave survex path '{{  cave.area.all.0.kat_area }}/{{cave.kataster_number}}'
     <div id='scene'></div>
 {% endif %}
 {% if cave.underground_description %}