grasping the concept of shadows is a much difficult task. this will help make near realistic shadows.

Note: never use a drop shadow on a car. drop shadows do not look like real shadows and make the car look real bad.

im going to assume this is a chop in the state of a signature, so the car is already cut out and on a white background for our purpose.

from here, step one will be to duplicate the car layer, and hold down the Ctrl button and click on the thumbnail of the car layer in the Layers window. this will create a selection of everything on the layer of the car.

after that, you want to press the D key, which will change the foreground/background colors back to black and white (black on top). then go to Edit > Fill and fill the selected area on the new layer with the foreground color.



next you want to transform the shadow to make it appear flat, as if its on the ground. press Ctrl+T to enter Free Transform mode, and stretch/skew the image to appear on the ground.

Note: dont forget to erase any odd areas (specifically around the wheels with this image >>> when you skew this shadow, a small part will appear behind the front wheel... but the way the shadow is facing, there would not really be a shadow behind the wheel, so you want to remove that area carefully.



now, shadows dont conform to the original objects shape perfectly in real life, so were gonna need to blur the shadow a bit, but not too much where it loses all of its shape. to do this, you want to add a little bit of gaussian blur ( Filter > Blur > Gaussain Blur). i set the filter to about a 2.4 pixel radius.



after adding gaussain blur, you notice the shadow to take a more natural effect... but it still isnt convincing enough. so lets blur it more. i then went in and added another gaussain blur filter, and this time set the radius to 5.0



but wait, that doesnt look too good does it? the problem is, that with a real shadow, the farther away from the object, the more blur there will be. but instead we just added more blur everywhere.

so to fix this (backtrack your document to the previous step), we will instead go into Quick Mask mode (Q key). select the gradient tool.

Note: make sure you have the default color settings (D key -- black as foreground, white as background).

switch the gradient to the black fading to transparent (it should be the second gradient assuming you didnt make any changes to the gradient order).



after you select that gradient (make sure youre still in Quick Mask mode... you should be... but i cant guarantee you didnt screw somethin up)

anyways, now drag the gradient tool from the peak of the shadow to somewhere near the start of the shadow. i started out at about the peak of the shadow and dragged somewhere to near the passenger side fog light...

you want a good transition from solid mask to no mask.



now exit Quick Mask mode. you will notice that about half of the shadow is selected. dont worry, that is exactly what we want.

now go add the next filter of gaussain blur. i used a radius of 5.0



now our shadow is starting to take.... errr lose shape. in a good way

as you notice, the heavier blur is only around the "top/peak" side of the shadow, and as it gets closer to the car it fades out.

now that we have the blur down, we still dont have any transition between the lighter areas of the shadow where the shadow sticks out from the car, and where it should be darker in places where the shadow sits under the car.

to do this, lets add a Layer Mask onto the shadow layer, by pressing the button at the bottom of the layers palette that the arrow points to. notice the other arrow points to the layer mask thumbnail that was created... that arrow is just for reference.



now we will again, use the gradient tool with the black to transparent setting to drag in the same mannor as we did before to make the shadow start to fade out.

Note: Quick Mask mode is not used in this step.

you will have to do this last step quite a few times till you achieve a gradience that you like.



now see how much better that looks?

you will achieve a better looking shadow when you create shadows that are shorter/closer to the car... but the distance of the shadow used in this tutorial was sufficient to show the effects in each step.

 

Stickied