Excuse me! When exporting model ,how to correctly reset coordinate zero so that model can be well in other softwares? I often use "Ctrl +A",but I think that there must be something wrong. Thanks.

If I understand this correctly I usually make sure my cursor is at center and then with the object selected (if it is a single object) using the keyboard shortcut "shift S" and choose selection to cursor and that will bring it to center I would also make sure I have applied scale and rotation that usually will export the object out and when imported to another application it will be in the center

In addition to what Lobo said, to make sure your cursor is at the center, click N, and when the toolbar appears on the right, look for 3D Cursor Location, and then make sure the X, Y and Z coordinates all say 0.00000.

Thanks Miss B forgot that one

The first thing you'll want to do is hit "Shift C" which will place the 3D cursor directly in the center of the grid. (Zero position)

Then, as Lobo3433 mentioned, "Shift S" will allow you, with a pop up menu, to Snap the selection (your selected object) to the cursor.

You may need to do a third step though, which is to set, or reset, the origin of your object. If the origin of your object is somehow incorrect, or not exactly where you want it to be, then "Shift S" won't place the object exactly center where you might expect it. For example, with a human figure, you will most likely want the origin point to be at the feet. If the origin were set to the center of the model (its waist area for example) then that is where the "shift S" will snap your model to, resulting in its legs going through the grid floor. Therefore, you may need to use the "shift-alt-center C" key combination to set the correct origin for your model/object. (If the first two things worked though, then the origin of your selected object is probably OK.) Let me know if you have more questions regarding this step, because it can be confusing. It was for me in the beginning at least.

Also, make sure your export and import settings, specifically scale and axis, are correct for the program you plan on exporting to.

Erock3D

Thanks . And Miss B "OK . . . Where's my chocolate?" What about Lobo is your chocolate???