Is there a way to make only the shadow of a unit appear, and not his actor?

I don't have the editor, but try to mess with the cloaking properties?

Or maybe even air units..

I created a Buff Behaviour that cloaks.
After that, I found out I could simply modify the units' Flags to set them as cloaked.
Both ways work very well to cloak, but none shows the shadow...
And if I could remove that cloaked effect that alters the terrain, it'd be cool too.

If you want a unit with only a shadow you can use actor events to do it. Create a new event for the actor you want. Set the event to Actor Creation and set the message to set opacity. Change the opacity to something very small (0.01).

I think you could simply remove the model of the actual unit, not sure though.

Yeah, this will work, the smallest setting is .0001. You'll get a couple weird effects on some models (I think it may still try to not draw the shadow when the model is in front of it), but you won't see it if you aren't looking for it.

I haven't noticed any weird things. Maybe it depends on what your in game settings are?

The best solution would be to make a custom model that is a shadow (so that even people playing on the lowest settings can see it)

I tried it with a marine, but I only noticed a bit of distortion at the feed, where normally the shadow would meet the unit.

Edit: It's when you click above the unit and it runs over where the arrows show up on the ground, you can see the outline of the unit against it. That's what I was seeing.

Isn't the shadow based on the model itself?
How can I extract shadow's model? :S

You can't . There is no shadow model you would need to create your own. Thats why it wasn't my first suggestion, it is not very practical for everyone.

I don't know if SCII uses raytracing or realistic/dynamic shadows, but if it does and you use a shadow model, you'd need to either guarantee that the light will always come from one direction relative to the unit... or settle for a plain, late-90s-console-game-style circular shadow. I think.

The point of the game I wanted to create was to guess the unit that was moving around based on its shadow.
I guess I'll have to scrap the whole idea?

I wonder if it might be possible to use a texture or shader on the model that renders as invisible but still casts shadows... Have you tried looking into altering the model's textures?

This will still work with the opacity suggestion I gave earlier. It will not work for people with low graphics settings, shadows are rendered differently for people on this setting.

I already sense my inability at achieving such a thing.
Any chance you could write a wiki?
http://www.staredit.net/w2/index.php?title=Show_only_the_shadow_of_units&action=edit&redlink=1

It's pretty simple, go do Modules->Data->Actors, and find the actor for the unit you want. In my case I found Marine. Then look under the events (Event - Events+ in table view mode). Right click the box, hit add event. Change the event MSG Type to Unit Birth, and the action MSG Type to Set Opacity. The just change the value in the second box to .0001.

It is done

Just wondering: what happens when opacity is set to 0? ;o
And what if the guy is at low? He still see the whole unit or what?

Temps says to use Msg Type "Actor Creation" while shmeeps says to use "Unit Birth". Who's right?

And thanks for the wiki! <3

If it is set to 0, neither the unit nor the shadow will render. It's essentially the same as using the No Draw flag, but you can still select and order the unit, which I believe you can't if you just use the No Draw Flag.

As far as actor creation vs unit birth, unit birth is whenever the actor is attached to a newly created unit (I believe), whereas actor creation is when the actor itself is created. They both work, but Unit Birth would work if you just used the actor without attaching it to the unit. I think.

Actor creation occurs after unit birth. You can check this, looking at the units already created their UnitBirth actually creates the actor.