View Full Version : [Award Winner] Structural Shadows in Photoshop

03-23-2010, 12:41 AM
Okay, so someone requested a tutorial on the shadows that show up on my battle maps. Here's the sum of it.

In the picture below you can see that you have to designate where your light source is, and what your colliding against. Obviously.

03-23-2010, 12:45 AM
Light, generally, travels in a straight line. So draw reference lines from the center of your light, to the edges of your object. If you want to get really detailed, draw a line from the furthest and the nearest edges, that will not only give you the minimum shadows, but the maximum shadows. I don't generally have that much patience, so I use the center.

03-23-2010, 01:05 AM
Here's where you get to make a decision. Do you want to take the easy way or the pretty way? I added a texture to the background for giggles.

Easy way: See Figure 3a. Select the area between the rays. Apply a radial gradient (Black to white with the center balance at 75% to white, look at the gradient picture.) that starts at the center of the column and extends out as far out as you think your shadow should go.

Pretty way: See Figure 3b. Generate a profile of the collision object from the point of view of the height of the light. It can get rather complicated, but if you take your time, you'll have excellent results. As you can see, I didn't really take my time with my profile. I find it most beneficial if you can stick to paths in lieu of the raster masks. Using free transform, position the profile to line up with the shadow extents. (See Figure 4b).

After you have the shadow in place, change the blending type to something more appropriate. Multiply or one of the Burns. Stay away from the Light section as it tends to alter the picture in the white section as well as the black, and we don't want that.

03-23-2010, 01:31 AM
Now it's time to soften the shadow. As it stands, it's not exactly attractive.

Easy: Select the area around the shadow (Go bigger then the rays, you'll need to have space for the blur to work.) Try to start one corner of the selection box or area exactly on the column. We're going to be using the radial blurs and it's mighty difficult to try to position the center of the blur in the exact location. The program interprets the extents based off page and/or selection. Hence the effort to try to make the column one of the corners of the selection. Apply a radial spin blur (I used 10 px in the tutorial images) and move the origin of the blur to the column. Change the opacity of the layer to somewhere near 50% and boom! You have a shadow. (see figure 4a).

Pretty: Again with the complicated selection from the easy section. This time, however, apply a zoom radial blur first. It softens up the edges better. I used 10px zoom, and make sure to move the center to the column. Then apply the radial zoom and again, Boom! (Figure 5a) you have a shadow.

Additional tips:
if you're using the Sun as your light source, decide the angle of incidence and use that for every shadow angle. 45 shows up pretty well for most maps.
When using multiple light sources, make sure you calculate each light individually and in their own layers. That ensures darker shadows when they actually overlap.
Don't be afraid to futz with the edges with a blur tool to make it look exactly the way you want it.
If you have a shadow that continues out to infinity, skip the gradient and go with a solid black.


Good luck. Sorry for the highly unstructured method of my tutorial. I find that design is fluid and sticking to numbers gets me in trouble. I intend this to be a general guideline. Like cooking, the best comes out of personal tastes.

03-23-2010, 02:26 AM
This is really good. I'll probably never use it, being a whore for 3d software. But I will rep you, 'cause it is seriously cool.

03-23-2010, 07:41 AM
Great tutorial! I'd rep you, but a little pop-up box just told me I have to "spread it around" before I can give you more rep (oh well, it's the thought that counts).

Steel General
03-23-2010, 07:47 AM
Nice, thx for posting.

03-23-2010, 11:01 AM
Wow. I didn't expect to see it this quickly. Awesome stuff. Thanks!

03-23-2010, 11:28 AM
this is good stuff PW, thanks for sharing!! By any chance you also have a good trick for shadows casted on other structures? cheers!

03-23-2010, 01:31 PM
Great stuff. Just one note - if you have 2 overlaping shadows they only combine to create a darker shadow if they are shadows cast by two separate light sources. Otherwise the shadow should be just as dark in the overlap as for the darkest point of each individual shadow.

Good tips on the radial blur and the zoom radial blur. I'll definitely use those. Thanks!

03-23-2010, 03:00 PM
You're right, I was a little unclear. You can see in the attached picture, that the shadows cast by the trees from the firepit are the same density. But there's a small triangle of darker shadow where the torchlight and the firelight both "miss" the area.

03-24-2010, 05:10 AM
Awesome, i was just looking around for something like this. Repped.


03-24-2010, 02:55 PM
Yes very nice and repped from me too. Tho I concur with su-liam there's a point at which you can get a lot of this for free in a 3D app. You have to balance whether the shadows or making the 3D objects is more of a chore.

03-27-2010, 01:15 PM
What 3D app do you guys use?

03-27-2010, 01:51 PM
Which software? Like our choice of mapping apps, it varies.

Redrobes primarily uses his own software that he developed/developes - see his Sig.

Many use Sketch up, because its Free software. Robbie the Admin (Arcana) uses 3D Studio Max, but then he uses it in his workplace as well. There are users of Vue, Vue d' Esprit, Caligari Truespace, and many other apps. Light and shadow is intrinsic to 3D software to help depict "3D", so yeah using a 3D app to build your terrain and map objects grants free applications of shadowing.

I use Nendo 1.0 as my 3D modeler - simple, fast, powerful/capable and cheap. Then I usually use my old Raydream Studio for rendering, though I have other more expensive 3D apps as well - Nichimen Mirai and Cinema 4D. Raydream isn't as good, as those two, but is easier to use - and having used it for ten years its a faster production flow for me.

Sometimes to create 3D plants - trees, ground cover, and aquatic flora, I use PD Particles a really cool and unique node-based painting application with all kinds of unique brushes (for leaves, conifer needles, grass, etc) object color tool to modify colors, and setting parameters to change how the nodes "flow" - its difficult to explain without using it, but when I need realistic looking plants, I use it quite a bit. Though in many ways, 3D apps are better, they are also more expensive, more complicated requiring more time to create objects, PD particles is fast and easy to use.

There are many options for 3D, so we all use what's comfortable to us, or what we can afford.


03-27-2010, 03:09 PM
I use Maya and am starting to learn Houdini, but both of those are outrageously expensive and targeted toward the film industry. I haven't yet applied Maya to mapping tasks, although I'm planning on building a modern cityscape in the near future for a short film, so I may just make a map as a part of that project.

I'm surprised GP didn't mention Blender3d, which is an open source package. It's quite powerful, although difficult to use. It's not so much harder to learn than Maya or 3ds Max, though, in my opinion. It's just a little less well-organized.