Hello. I’m new to Zbrush and I’m using Zbrush2 and I was working on a Zspheres model and ive saved it onto my desktop as a .zbr document, but when i went back to the document it didn’t let me edit it and but new zspheres in it can someone answer my question?
Hey Phoenixknight,
You want to save out your zspheres as a ZTOOL under the Tool/Save As/.ztl. And then you can continue where you had left off with an editable zspheres/mesh next time when you want to work on your zspheres. To do this you can either when you first startup zbrush LOAD TOOL option and browse to where you saved it out before. Or when you are inside of Zbrush you can go to Tool/Load Tool and re-import that way.
When you save out the Document zbrush turns your editable mesh into a 2D image instead of 2.5D. It retains the lighting information though which you could change (Light position,intensity,shadows etc.) But, you no longer have the ablity to edit the mesh other then 2D Brushes.
Hope This Helps.
Thanks for the help NewToTheGame I have one more question: Does Zbrush2 have a edge loop tool or do i have to download it from a site or what do i need to do to get the tool. 
ZBrush 2 does have the Edge Loop feature. It’s found in the Tool>Geometry menu. But it’s only available if your model is a polymesh. So if you’re working with ZSpheres you’ll need to make an adaptive skin and select that before you’ll have access to the advanced editing features.
The reason for this is that ZSpheres are an object generator. Sort of like NURBS on steroids. And like with NURBS, you can’t edit the object on a polygonal level until you’ve made it editable by detaching it from the generator.
Put another way, while you are working with ZSpheres the object’s polygonal structure can still be changed. All it takes is adding or deleting a ZSphere, which would then calculate a whole new skin when you turn on the preview. Because the preview is so easily changed, it doesn’t make sense to let you start using features that modify the polygon structure like Edge Loops.
Im lookin at the polymesh 3D under the tool section but the edge tool doesnt show up. What am I doing wrong? 