Sketchup model missing on window

actually am working with my model but i select zoom extends suddenly the sketchup model disappear how i can get my model views ,

Attach your model so we can check it.

You may have a stray geometry far away from your model.

When you select Zoom Extend, SU shows everything, including that stray geometry. This means that the model get shined to a nearly invisible speck to allow the showing of all the space used for modelling.

If you want to check for that, try this procedure:

1 - Use a view that show the useful part of the model.

2 - Click on the Select Tool or press the Space Bar key (the usual shortcut for Select Tool).

3 - Do a select all (CTRL-A if you prefer). This will select what you see as well as any stray geometry.

4 - Press and hold down the Shift key to add/subtract to/from the selection. A small + and - sign appears when you press the Shift key.

5 - While still pressing the Shift key, select the main part that you want to keep. You can do a window select for that. This deselect it. What remains selected is the stray geometry.

6 - Press the delete key.

Now, try a Zoom Extend to see the result.

If unsure, do as Box indicated it, attach the model. Use the eight icon from the left in the bar of icons that shows above your post, the one with a small up arrow.