Question: The “Export to Sketchfab” option seems to be broken.  How do I upload to Sketchfab and what settings to I need to change to get good results?

I just uploaded this model: 

I did change Z Scale to be 2.5, but left Explode at 20, which gives me this in the viewer:
But don’t expect to get the legend in Sketchfab, since it is not a 3D Legend.
I did “Use Textures” (as you always should). 
and I used this (write) VRML option
It uploaded quickly (which was surprising for a 36Mb file), but it did take 7-10 minutes to “process”.
Once your model is “Ready” for editing on Sketchfab’s page, you want to choose 3D Settings
The settings are organized in Categories and then Tabs:
We’ll start with the Scene Category
On the General Tab, be sure to choose both “Classic” and Lit (Shading).
On the Camera Tab, the only thing that you might adjust is the Field of View.  Normally in EVS, we use an orthographic view which has Perspective turned off.  This would be equivalent to a theoretical zero degree field of view, viewing the model from an infinite distance.  The default 45 degree FOV is very wide and creates a lot of distortion (for my taste).  You might want to decrease this to 20 degrees or less.
Leave Wireframe Off, and go to the Vertex Color Tab:
Make sure it is set to sRGB
For the Background Tab, we recommend using the Color option
Below shows how to select a Black background (lower left corner).  If you wanted White, it would be the upper left corner.
Now we move to the all important Light Category, and the first thing we need to do is turn the lights ON.
Just having the lights on makes a big improvement, but the default lights are awful and really need to be edited.  To edit each light, you click on them, and a LOT of new options appear.  I’ll go through the process of editing only the first light, but you’ll want to do similar things for all three.
The critical things to select and/or change are:
  • Light Type
  • Light Color & Intensity
  • Light Direction

The less important (artistic) decision is whether you want your light(s) to “Cast shadows”.  I often turn this option ON, but for my PRIMARY light on this model with multiple (closely spaced) layers, I will not.

Unless you have some compelling reason, all lights should be WHITE.  When you are editing each light’s direction, it is easiest if you turn the other lights OFF.  Below you can see my model, with only the first Directional light (now white) coming from above, over the observer’s right shoulder.  Direction(al) lights are generally the best choice, though I occasionally use Spot or Point lights in some models.

Changing the direction of the lights is a bit tricky.  There are three circles that envelope each light.  Clicking on one of the circles defines the direction of rotation for the light.  It takes time to get comfortable with this.  The position of the lights is irrelevant.  I’ve moved mine to make them easier to see, but moving them is trickier still.  The Direction(al) lights are like light from our Sun.  The light is parallel, uniform and everywhere, so the absolute position of the light doesn’t matter.  If you want to play with Spot or Point lights, their position in your model space matters a lot.

With the second and third lights we want different directions and intensities so we don’t throw so much light on the model and wash out our colors.  We also want to take care of the dark areas (but don’t worry too much about that here).    As you can see my 2nd and 3rd lights are lower intensity and the 3rd has Cast shadows ON.

At this point our model looks much better!  My second light points upward, which is important if we want the bottoms of our layers lit!
I’m going to skip over the Ground Shadows Tab.  You can experiment with it if you want.
The Environment Tab is very important.  Once again, we need to choose a Black & White environment so that the lighting doesn’t introduce any false colors into our model.  This can be tricky because Sketchfab keeps changing the environments that seem to be available!  You can get by with only your 3 lights, but you won’t have an Ambient light source.  You may even want to go back and readjust your 3 lights after you set your background brightness, since this option can do so much.  If it is there, choose the “Studio” environment and try these settings:
The only remaining Category of interest is Annotations and it isn’t necessary.  You can experiment with it, but I’m not going to do so here since it doesn’t affect the quality of the display.    Click on the Scene Category (just to make the light interactors go away), and at this point we’re ready to save our model.
All that is left to do is rotate and zoom to the view you want to have when the model is opened, and:
  • Click Save View, and
  • Save Settings or Save and Publish