This is Toad's Tool 64, the VERY first (I mean it, however surprising) Super Mario 64 Level Editor!
Toad's Tool 64 RELEASED! Download here.
FEATURES AND LIMITATIONS (MODIFIED BY NEW POSTS) (Written by VL-Tone in his blog)
• Move objects found in levels using an on-screen widget, keyboard or by changing their x,y and z values.
• Move objects by dragging them on the screen.
• Rotate some objects (type 0x24 and 0x42) using the on-screen positioning widget or little rotating widgets.
• Change the objects 3d models and behaviors using preset lists. (ie: change a Goomba to a Koopa)
• Edit the object description labels used in the editor, and add labels for new combinations you create.
• Click on objects in the 3d view to select them, or use the object list on the left.
• Select multiple objects, move them, change their model IDs and other parameters all at once.
• Copy and paste selected parameters between objects.
• Copy a raw Hex dump of the currently selected object to the clipboard.
• An address field showing the absolute ROM address of the currently selected object.
• If you enter an address in this field and hit return, TT64 will find and select the associated object.
• Revert the selected object to the last saved version.
• Show only selection boxes for the current command, all commands, or only the selected object.
• For 0x24 objects, you'll be able to change which "act" includes a particular object.
• Set the level music.
• Set warps destination level, area and warp object.
• The editor will provide a list of possible 0x26 or 0x27 warp destinations in the target level.
• The "Save" button will turn red when you have unsaved changes.
• Front, Back, Top, Left and Right cameras that can optionally follow the current selection.
• The "Fly" camera mode enables you to fly around the level much like in the Peach Castle Demo.
• The "Orbit" camera can rotate around the selected object and will follow it.
• An on-screen widget to move the camera around, with relative or absolute control.
• Wireframe mode.
• Switching face culling on and off.
• Choosing between orthographic or perspective rendering.
• This level editor won't edit polygon shapes.
• Most levels have a basic polygonal structure (ie: ground and walls) that can't be changed.
• You'll be able to move objects and most platforms, but don't expect to be able to reshape the terrain.
• Many enemies and characters won't display correctly (ie. anything that has rotating joints)
• Some description labels may be missing.
• In some condition, transparent textures will have glitches associated with a Z-Buffer bug in Shockwave.
• Tick Tock Clock is the most affected by this.
• While you'll be able to change the input and output targets for warp commands 0x26 (and 0x27), you'll have to manually find which 0x24,0x42 or 0x43 objects use these warps conduits. Completing a list of all warp behaviors will enable a future version of the editor to achieve this automatically.
• In the Advanced and Expert commands mode you'll be able to view some commands that won't be editable.
• I'm still hesitant to add the ability to edit 0x21 and 0x22 commands in this version.
• This editor won't take 0x00, 0x17, 0x18 and 0x1A command parameters into account, it uses a pre-built list.
• This means level scripts and ROM "banks" can't be extended or moved.
• The first time you’ll run the editor, it will spend a few minutes building a file containing pre-decoded polygon data, to make things faster. This will only happen on the first-run.
Credit to Qubed Studios, editor is as yet uncopyrighted.