Problem modeling in perspective view When I arrange vertex in a shape in front perspective view and when I move them forward from side view the shape looks bigger as it comes forward in front perspective view and when every time I move it forward I need to shrink it to make it look same the same size as it looks before, this takes a lot of time for modeling. Is there any way to shrink the model as it comes forward so that it looks the same size as it looks before?
Perspective, while it is the way we see things in the real world, is an illusion. 

These train tracks look like they are converging, but obviously they can't be.

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Orthographic projection is a way of seeing 3D shapes in 2D at their actual sizes, without perspective distortion.

Here is a comparison of orthographic versus perspective, with the same camera angle.

 

The orthographic version doesn't look "right", but the tracks appear parallel, which is how they actually are.

By moving the camera backwards and increasing the focal length, you can kind of get an ortho-like look.



Assuming you are modeling from an orthographic or nearly orthographic reference image (obviously it is impossible to get a true orthographic projection from a camera, but photographs can be "close enough" if taken with a long focal length), modeling in ortho is the best way to go. It does take a little getting used to though..