How can I load an original Doom 2 map in doombuilder?

I want to experiment with some of the original maps. Is there a way to access them?

Just ... open the wad in the map editor. Vanilla Doom configuration obviously.

You can just open your Doom 2 wad.

After loading an IWAD map, I recommend immediately using "File -> Save Map Into" to copy and save it into a different file, so that you won't accidentally modify your IWAD by editing and saving the map in it.

Ah, thank you guys.

And thank you Scifista. Good idea.

And if you use GZDoomBuilder's "Save map into" then you can save the modified map by itself in a new wad. And maybe into an existing wad, too(?)

EDIT: Too slow, delete me.

VGA said:

And maybe into an existing wad, too(?)

Yes, that's actually the main purpose of "Save Map Into". On the contrary, "Save Map As" - when applied on an existing file - simply overwrites the file and removes all its previous content.

This might have been useful in my Redux project.

"Save Map Into" still overwrites a map in the same mapslot as the map currently being saved - in other words, saving a MAP01 into a wad which already contains a MAP01 will overwrite the original one, and so the new MAP01's mapslot needs to be changed in Map Options before saving it. Or you could just use SLADE3 to copy/paste and rename maps easily, quickly and in whatever order.