Technical art questions and discussions

Started by Andail, Wed 25/05/2005 19:46:07

Previous topic - Next topic

TheJBurger

I have some technical/artistical questions about certain aspects of drawing, and if anyone has the answers for me, that'd be great.

Lighting:
Light beams - When to, and when not to use them.

I've frequently been experimenting in lighting in a lot of the backgrounds I draw, and particularly with concentrated light sources. Sometimes I use "light beams" that come from an opening to create a dramatic effect, but I really have no idea about the technical aspect of when they really exist, and when to use them.

E.g.
Case 1:
This one was made for the background blitz awhile ago. I'd seen similiar pictures with light beams in a similiar enviroment, so I just copied the idea. I don't know if this really exists in nature though.

Case 2:
This was a sketch I made a little while back. It's supposed to be a run down room on a second story with one window on the side. I originally used a very strong beam of light coming from the window but I toned it down so now you can't tell too much that the beam exists, or if it's just lighting on the walls.

So my question is, when is it ok to use strong light beams? Or should you even use them at all?

Bounce light
So I've been reading about this thing called bounce light that causes the opposite side of an object to illuminate with another color. I guess this would generally be the color of the opposing light source. In outdoor scenes, should there always be a bounce light then? And would this be a blue bounce light?
Most backgrounds in A Tale of Two Kingdoms have blue bounce light on outdoor objects like trees (sorry, I couldn't find a good screenshot at the moment). Is this correct to do from an technical perspective?

General lighting
(Without having any professional knowledge) My guess is to light all objects with a hue of color from the light sources and a lesser hue from the bounce light. Would that always be a brightish yellow white for the front lighting and a blueish bounce light for outdoor scenes?

Azaron

First off, the light beams: These occur naturally, but only when there is some sort of particulate in the air. You only perceive light if it hits something, so in order to see a beam of light, there must be some sort of dust or water vapor or other gas in the air for it to bounce off of. Otherwise it is invisible to you. Now, the more dense the concentration of particulate, the brighter and more defined the beam will be... TO A POINT. If there is too much particulate, it will scatter the light and wash out your field of vision. Walk outside during an early morning heavy fog, and you will see this effect. Or turn on the high beams in a car in a misty area. It will literally make it impossible to see anything beyond the vapor in the air.

So, I would say as far as using beams in your art, they can be used to affect the mood of a piece, but keep in mind that using them will give the piece a sense of heaviness in the air, as well as allowing you to draw focus to something. ie: in your forest piece there, the beams draw my attention to the opening in the rock face, but also give the impression that the area is very humid (which, judging by the look of the foliage, it is. Good work :) ), or very dirty (lots of pollen in the air, although if there was enough there to effect beams like that you wouldn't be able to breathe ;) ). I also get the impression that the scene takes place early in the day, because that is the time that moisture tends to "burn off" of evaporate into the air.
For the room, a light beam coming through the window would definitely give the impression of a lot of dust hanging in the air, but it would also be a little harsh to look at if it was too bright and may wash out important details behind it. In some cases it can make a room look smaller too.

Bounce light is just that: light that bounces. Objects reflect their color and absorb other light, so any light being reflected off of an object will be the same color as the reflecting object. You also have to take the object's surface into account. A rough surface will diffuse the light to the point that it will be negligible, but a shiny or smooth object may actually reflect a great deal of light. The reflected light will lose some of it's intensity, however, so no reflected light will ever be as strong as the initial light source unless it's reflecting off of a mirror.
Loominus just posted an EXCELLENT tutorial about light in one of Hillbilly's threads in the CL, so take a look. It's good stuff.

ZayanM

Regarding cast shadows in backgrounds:
How does one know what type of shadow to draw? Sometimes the shadows are blurred and at other times quite distinct. It gets more complicated when the shadow falls on irregular shaped objects. Also, how can you figure out the angle and length of the shadow?
I've been looking this up online, but I still cannot figure how to implement it in a game background.

Help would be appreciated. Thanks.

scotch

Bounced light:

As Azaron pointed out, there's no reason for bounced light to become the opposite hue to the lightsource. Bounced light takes on the apparent colour of what it bounced off (which is why you see things that colour in the first place). There's currently a lot of green light pouring upwards through my window, because of the way the sunlight is on the grass here in the morning. People do often backlight things with a complementary colour though. It's common in the real world (diffuse blue sky light vs yellow sunlight) and creates a contrast. It's not bounced light so much as ambient light in that case.

Shadow hardness:

The hardness of a shadow is defined by the distance the shadow is from the shadow casting edge, and the size and distance of the light source. A perfect point light would only make hard edged shadows (directly), but real world lights generally have some noticable area. Essentially it's about how much of a light source's area is obscured at a particular point on the surface. Imagine you are looking at the light from that position on the surface. What percentage of the light's area is blocked? As you walk into the shadow, more of the light source is becoming invisible to you, so it gets gradually darker. The smaller the light source the faster this happens, and the harder the shadow is.



Obviously as the shadow casting edge gets closer to the surface it's casting onto, the shadow becomes harder and harder.

You can construct the shape of the shadow with perspective rules, but luckily in most cases you should be able to eyeball it. Lower lightsources equal longer shadows of course...

radiowaves

#44
Shadows depend on light strength and material the light is directed. Sharp shadows, distinguishable shapes are caused usually by direct light. Usually the edges of the shadow shapes blend a little when the material is soft or there is something else reflecting the light (a bright surface).
When light is indirect, shadows are blended so that their shape becomes almost indistinguishable. This is because of the physics that light particles have. When light ends, in an unreachable point, the rays still bounce forfard, causing the effect of fading shadows and light reflections on surrounding objects. Therefore scotch's picture is not 100% true. His sunrays would still produce quite sharp edges, but not complete fading.

If you take a cube for example and put it under direct light from one side, you see that the shadow it has is actually lighter in the inner section when its closer to the cube, same goes with the shadow on the cube that is closer to the floor surface. That is caused because of the light beams reflect and bounce from different surfaces to another.

Some examples:



And this famous Edward Hoppers painting:


Notice how the closest wall in a shadow is actually greenish-yellow instead of blue. That is due to a colour reflection. Remember, shadows aren't black and white, they are actually coloured. Usually the rule is that warm colours have cold shadows and vice versa. And in cold colours, reflection of warm colours pops out. But that is not always 100% true, still, it would be enough for you I think.

Also remember, that those reflections in shadow, the bouncing light etc, are not just light, its actually colour of different surfaces that shine and reflect on each other with light. So, when you have a blue cube on yellow surface for example, some of the bright yellow is reflected on the cube. Always remember that brighter colour reflects more on darker colour and all bright areas reflect light.
If you look at some pictures, where perspectively and what-so-ever all seems to be correct, objects have shadows etc, but still parts of the image look weird and unnatural, know that usually the problem lies in missing colour reflections. I always try to lend colours of different objects onto the surfaces of others when doing my pictures, so the whole piece would feel like a whole where everything is fitted together and not scattered floating pieces. That is also the reason why most of the pixelartists try using lesser colours, it can be taken as a practice in lightning and colour composition.

But what can be really mind puzzling are the reflections and shadows on different shapes. For that, I've actually collected a few tutorials which can be found on a sidearm of my homepage: http://www.clicksandbleeps.com/tuts.html

Thats all! I am not smart and diligent enough to continue writing on this topic, so I end thi here for now, hope it helped :)


As with sunbeams, most of the above was true, but lets not forget that sunbeams cannot come from clear sky in an open area. Thick beams of light need a dark area with sharp light source (a hole in the ceiling). And on some occasions, when the light is very very strong and due to a structure of source, beams can appear in non-thick air too. And the main rule is that area needs to be darker than usual so the beams can shine out.
I am just a shallow stereotype, so you should take into consideration that my opinion has no great value to you.

Tracks

scotch

My picture isn't of the sun, it's of nearby light sources of various sizes. Sorry if it's not clear enough from the shape of the shadow that the light is fairly close to the object, and not a 150 million miles away. The sun does occupy a relatively small area in the sky, so its shadows are indeed quite sharp. Usually between the first and second images in a typical scene.

ZayanM

Hey thanks for the replies, plenty of useful information (including the link)  :). I didn't think shadows would be for me the tricky part of the backgrounds but they turned out to be so. Still implementing shadows in a game background is proving slightly perplexing, which more practice should fix.

Oliwerko

Hello there guys.

I am working on a BG and it's giving me a hard time.
It's a garage, and I want a vehicle in it. But everytime I try it turns out that it sucks. I'm not posting the BG here, because I would probably in depths of my mind copy somebody's repaint.  :)

All I want to know is: How do you people draw vehicles ? What are your techniques ?

Oddysseus

I find a picture of a car from the right angle on Google Images.  Then I scale down the image so it fits in the background, and save that version of the picture.  After that, I usually trace over the outline of the smaller image, and use the bigger image as a reference for the highlights/shadows/etc.

Some people would consider tracing over a scaled-down image "cheating," but I prefer the precision of that method.

Oliwerko

Wow, that's pretty difficult, because of the perspective and so on. Don't you have problems finding a suitable image ?

zabnat

I would probably start with box or boxes as boxes are easy to draw in any perspective. Then refine the car shape inside the boxes maybe using some car blueprints and photos for reference.

Something similiar to technique used for making a 3d model of a car. See www.suurland.com for blueprints and tutorial for making a 3d model of the car.

I'm not sure if you understand anything from my explanation but it's pretty hard to explain. But you can take some important dots/corners/points from the blueprints (like the corner of the door) and then place it on the faces of your box (which is drawn in perspective), place it in the side face of your box and the top face and then draw lines to the same place on the other side of the box (for the top face draw the line from the dot from the top face to the similiar position on the bottom face) and then you find the correct place for that dot in the intersection of the lines. Add more dots and then draw lines between them and you have a picture of a car in perspective.

This is hard work, but if you have a good understanding of perspective you can cut some corners here. This is just one technique, I'm sure there are better ones...

Oliwerko

Yeah, i thing i've got it now. Started with boxes and developing it in layers on top of it in many steps. It's turning out nicer and nicer.

Thanks for tips boys  :)

Luke Lockhart

Here's my question, which is a bit more basic than most here, but it's somewhat important for me: how do I make my sprites look like each other from different angles? In other words, if I have a character and I draw her facing the screen, how do I make a new sprite of her facing to the side or away from the screen and have the drawing look as if it's the same person facing a different way, instead of an entirely different character?
If nothing we do matters, than all that matters is what we do.

I was once known as Luemlo.

zabnat

#53
To make it look like same character from different angles you should first create a character and then make a sprite of character. Sketch the character first and think about what basic geometric shapes it is composed of (think 3D). Then you can sketch it in different angles. After that you can start making a sprite.

Also this tutorial by ProgZmax at cgempire will be most helpful.

TheJBurger

2 Questions:

What is the golden ratio, and how does one use it in composition?
All I know about the golden ratio is that it is equal to 1.61803399 and it can be used in composition to achieve certain results. The only real info I've picked up on it is here.

So, how often should you apply the golden ratio to a picture, what uses does it have, and should you always put the focal point on it?

What elements can be used to strengthen a composition?
Off the top of my head, I can only guess
- Perspective: lead the eye to the focal point. What if you dont have/know what your focal point is?
- Lighting: Draw the eye to the focal point with darkness and brightness.
- Golden Ratio? Put objects in certain places on the backdrop?
- Foreground Elements/Overlapping objects: Create depth in the picture.

rock_chick

I'm not sure if this is the correct place to ask this but I've been looking all over for textures that are appropriate for games, mainly things like tiling for kitchens and bathrooms and carpet textures. The ones I have come across are a bit too realistic for my game(as in they are basically real pictures, even though my game using hi res graphics). Also most 3D design.
So does anyone know of a source or program(besides GIMP or maybe some links to plugins or whatnot for it that could be added to the program for these textures) for this sort of thing and also I need to make sure I can understand the credit and conditions of using them, mainly on websites are a bit unclear or want links back on a website(so they're designed for websites).

Oliwerko

I don't know if I get correctly what you want, but I think the best thing is to make everything by yourself. It takes away much of the rewarding feeling when you use someone else's work. If you can't draw something in sufficient detail, go for less detail, but for your own work.

I don't know for sure how it is in high res though. I make low res graphics for now, and things like tilings and so on can be easily made. Anyway, I would always go for my own work...

rock_chick

Again this may not be the correct place to ask but I've looked at all the tutorials in the tutorial section in the Critics Lounge and few explain for newbie's on computer drawing(not sketching on paper and then scanning it and such) how to learn how to draw simple stuff and maybe then harder stuff but in a sort of step by step guide. I want to learn how to draw but few tutorials give you an idea of how to use the tools in even simple programs like MS Paint(most are based on Adobe products) to really help newbies at this grasp an understanding of how to draw properly in simpler programs, the bare basic is what I'm getting at.

Oliwerko

Do you want to know how I started?

Well, I have read Eric's tutorials a few times, looked at Trilby a lot (and I mean a lot, 5DAS running in background) and then just popped up PS and tried to do the same thing. Then I got disappointed with results and half a year I have done nothing. But then I collected all my patience, and tried once more. I tried to draw a background, and it did not turn out very bad, actually.
One VERY important thing is to choose a good paint program that you feel comfortable in. I personally use ImageReady for animation, ArtGem for BGs and GraphicsGale for sprites. Start basic. Basic furniture like shelves, sofas, TVs, square things. Squares are easy.

But I guess all of these I have covered in my tutorial you have already probably read. In case not, do it, it is in the Tutorial thread in CL.

Trihan

I'm not sure if it's appropriate to post in this thread this long after the last reply, but given that it's a sticky and I won't be bumping it I guess it's not a problem.

Anyway, I have more or less the same problem as rock_chick. I used to be a fairly decent artist but through lack of practice I can't even draw a circle any more, let alone do a proper sketch on paper. Does anyone know of a way to practice and improve pixel art skills when you lack the basic tools of the trade and can't really afford them? Pixelling on a budget, if you will. There are loads of tutorials out there but none of them really give you a true step-by-step "do this along with me!" approach, which I think would be immensely useful.

SMF spam blocked by CleanTalk