April 2013 Video Tutorial: Making a Diffuse Shadow

[Gare]

Because April's Big News—the release of Web Designer 9—is the top story at the Xara Xone, I've made a shorter video tutorial this month, covering a real simple but elegant thing: the creation of a diffuse shadow using Live Effects in Xara Designer.

Watch it here

The reason I wrote this is because I'm seeing a lot of soft shadows like those Photoshop used to produce with the Gaussian Blur filter, and very crisp shadows, but not ones whose edges are rough, suggesting overcast lighting and/or a rough surface.

Let's talk about it here, and by the way, I created a tutorial and a Giveaway this month of seamless textures for web pages as a complement to Gary P.'s piece on WD9.

My Best,

Gary

[angelize]

Combining the diffuse and Gaussian blur Live effects to create a more realistic shadow is a good tip. I've blurred shadows, feathered shadows, used the diffuse on shadows I don't know why it never occurred to me to combine the diffuse and blur.

I've had this idea for a drawing kicking around in my head for a few weeks now this little tutorial inspired me to let it out!

[stygg2003]

Nice effects Francis and the drawing. I've just made the shadows as in the tut. I want to have a go at recreating that shiny sphere, it's really neat.

Stygg

[wizard509]

Good job stygg, I'd like to try that one myself when I get home.

[stygg2003]

Cheers Larry, those shadow effects look good on all spheres

Stygg

[angelize]

Thanks Stygg I'm thinking I may also post that drawing in the Xara art gallery forum where I can get a bit of feedback on the drawing it's self and not just the shadows.

I think these shadows look better when the surface they are cast on has some sort of texture to it.

[Gare]

@Frances-I like what you did, and yes, a floor really supports a shadow, literally and figuratively. It provides visual context. Your columns illustration is a hands-down winner, a terrific addition to your portfolio, I’m sure, quite photorealistic.

@stygg-Let me go O/T for just one moment. The pinball illustration is a product of a formula I’ve used for over 30 years for illustrating chrome. Ideally, what you see in a shiny object is its surroundings and the simplest environment is a sky, the horizon, and a ground, like this picture here. So I drew a pinball whose environment is a sparse interior: a windowpane and a distant light instead of a sky, and a wood paneled floor instead of a ground.

You can import a photo you take of such a scene, use Live Effects>Deformation Filters>Fisheye perspective, and then clip it to a circle to get a quick approximation of my little reflection recipe here. I added some soft highlights as you can see, after clipping the picture.




@Everyone-I hope this month’s tutorial has got you thinking about what you see in the world. The appearance of shadows is governed by two things: the lighting conditions in the scene (sunny days produce sharp shadows, overcast days produce soft or no shadows at all), and the surface upon which a shadow is cast-shiny surfaces prefer reflections to shadows while coarse surfaces such as sand can show sharp (sunny day) shadows with rough edges, or diffuse shadows on overcast days.


There’s also something called an Area light in modeling programs that simulates a unique lighting condition and an equally unique shadow, that’s also visible in the real world. Let’s say you’re in a bare room with bright white walls, and there’s a window from which is casting bright sunlight. And there’s a cube on the floor (the floor is smooth but not shiny). The shadow you’ll see will have sharp edges toward the base of the cube, and as the shadow travels away from the cube, the edges soften. Why? Because there is both direct and indirect lighting into the room. The sunlight through the window is direct and produces the sharp portion of the shadow, while a weak secondary source of light—reflections of the light bouncing off the walls—cause a softening of the otherwise sharp shadow edges as the shadow becomes weaker at its farthest point from the cube.



To imitate this effect in Xara, you need two Blend shapes and a fairly high number of blend steps (over 20, I’d say). The two shapes share a closeness at the edge closest to the base of the shape, and the other side of both the Blend shapes have a distance between them where they are farthest from the shape.



I’ve attached a Xara file with a cube and my version of direct + indirect lighting. You’ll see toward the front a certain sharpness of the shadow edge, and then it becomes diffuse. Not only did I use Blend steps but also Stained Glass mode transparency, a high degree of transparency because there’s a lot of Blend steps and I added Gaussian Blur Live Effects to the shadow drawing (possibly ruining some of the sharper areas!) to hide the banding of the Blend shapes. I like using Blends because you can mold the shape of a shadow any way you like it. The Shadow tool is fine for drop shadows on text and occasionally a floor shadow, but like any “do it for me” effect, it’s limited.

I think this stuff works: it plays and you yourself have to decide the amounts of the recipe elements to get your drawing where you want it to be.

[stygg2003]

Gary tried using some of the effects for shadow diffuse as you suggested on this drawing I did a while back but must admit I'm not happy about it, any pointers on what's wrong with it. I've tried a few ways but can't seem to get it right

Stygg

[Gare]

Stygg, usually folks shouldn't care about the position and shape of a shadow but instead make sure that a shadow exists in a composition: the absence of one is more important than the accuracy of one, usually.

However, I think you might be unhappy with this composition because the shape of the shadow is wrong as is its placement. It's not that you're suggesting moss or grass which would break up the shadow; the light is coming from the left on the device so the shadow would be toward the right.

Here: I've done a photometrically accurate approximation of what you've drawn. You can take two things away from this as drawing the scene goes:
1. The shadow is clearly to the right of the floating object because of where the highlights are on the object. Now, I've covered this reality in past videos, so when in doubt, review, and yep, I'm being a smarmy, preachy jerk here.
2. To force the idea that this is grass below the object, look at what's happening to the shadow in my render. The edges are rough, and also quite hard-edged because this is an outdoors scene, with hardly a cloud in the sky.




Sometimes it helps to go back to the concept, even when experimenting. This month's shadow? It would probably exist in an indoor scene, not outdoors, with a light source from above, and lots of secondary light sources such as walls, to give the outline a rough appearance. The floor also wouldn't be smooth.

Consider both object and lighting conditions before you go drawing and you'll most likely be assured of some photorealistic results!

My Best,

Gary

[stygg2003]

Thanks for the feed back Gary much appreciated, will re-do the shadow with the correct position and bare in mind it is outdoors.

Stygg