HOW-TO: Gradient effects

[Moltas]

First of all, I am not sure where to post this question, so if I am in the wrong place feel free to tell me. I am kinda new here you know...

Anyway, I have been trying to make some cool shadows and feel that I need some help here. If you place an object on a surface and put some light on it you get a shadow that is very sharp and dark near the objects base and gradually gets more and more "blurred" further away from the object. (Hope you get the picture)

Now, all of the tutorials that I found on this uses two layers. The first layer is sharp and the second is blurred. Using gradient masks they simply blend the two layers into each other. This is pretty good but not perfect. Below is an example:

For now concentrate on the shadow to the right. Can you spot the strange effect when the double shadows are blending? This is the effect I don't like.

The Shadow to the left is more accurate and was made in this way:
1. First I made a selection that surrounded the shadow except for the part closest to the object.
2. I applied some Gaussian blur. (I think it was 0,3 or something)
3. I moved the selection 10 px upwards and repeated step 2.
4. Step 3 was repeted until i had reached the top of the shadow.

This can also be used to mimick a shart focal depth:

Again the right image looks strange.

Finally I made a quick image demonstrating both of the effects:

(I know that the green tube has incorrect lighting, I was not thinking at the moment )

This is my dirty way of doing it, but I suspect that it can be done better. If anyone understands what I am mumbling about and have some ideas please step forward

/Moltas

 

[MsOz]

Read up on Gradient Masks. I'm sure you will find them to give you a much smoother blur effect for your shadows.

 

[Moltas]

Hmm, I really have tried to use gradient masks but I can't stop getting the effect of sharp shadow overlapping blurred shadow (or vice versa)

But thanx anyway.

 

[Stroker]

If you have PS CS, Lens Blur will do it perfectly.
I took it for a spin once and was very impressed.
For PS 7 and earlier, I haven't been able to find an acceptable way of going about it.

 

[Moltas]

[saywhat] Well I got PS CS last week and I didn't realize that there was such an easy solution to my problem...

Thanks for enligtening me! I will check it out right away.

 

[Dodo]

I was quite impressed with the methods employed in the link below. But then, as an amateur, it doesn't take much to impress me .

http://www.informit.com/articles/article.asp?p=30311&redir=1

 

[Stroker]

Bert! Good choice, Dodo.

Well, this sucks. A few months after PS CS was released, several very excellant Lens Blur tutorials showed up in various 3D circles. Looks like they are all gone. At least I couldn't find any of them. Well, there are some out there, but the 3D ones, which were very good, seem to be gone. (I did find one 3D tutorial, but it was thin in comparision.)

Lens Blur and 3D
Do a regular render.
Do a z-depth render.
Get them into PS CS.
Use Lens Blur + z-depth render to fake depth-of-field (DoF) in realtime.

In a 3D prog, rendering DoF is rather expensive.
So, adding DoF in post is a *major* time saver in tweaking and rendering/rerendering.

If you get the gumption, wouldn't mind seeing some Lens Blur stuff that you come up with.