So, I thought it was time I showed the "secrets" behind my shading technique, even though I am nowhere near as good as I want to be. Still, some people have asked me about it, and so I started this tutorial thread, hoping that it is of some help to those people (and others who might want to give it a try someday).
1) Let's start with a basic shape. For the purposes of this tutorial, I use the
Enterprise's port nacelle, based on Alan Sinclair's schematics. The same principles apply to everything else, so this is really only an example.
2) Add some colours to the objects. This step is helpful in the long run, especially if you're just figuring out for yourself what you are creating here (if you're drawing your own shaded starship orthos, for instance). Having picked out the basic colours can spare you some trouble later, but don't forget that you can always change them if you discover that they don't work.
3) Add your first gradient and be amazed at how different the entire thing looks.
More later.
Posts
2) Let's add some shading to your details. It doesn't really matter when you do this, you might want to finish shading the basic shape first and then move on to the details.
Select the detail you want to add a gradient to.
Okay. This is going to be a bit tricky, since the intercooler (if that's the name for this bit; I don't have my TOS tech terms down pat yet) is angled. It'll take a few tries to get the gradient perpendicular to the main axis of the object, or at least close enough as makes no difference. When you're happy, modify the gradient to add darker and lighter areas. See the cropped gradient panel for information on how I did mine.
Next, add some shadows to the vertical edges of the object by creating some shapes where you want the shadows to be. I usually make a copy of the original object and cut off parts that I can use. Here I kept the leftmost curve of the intercooler shape and got rid of all the other stuff. I then connected the end points to give it a shape I was happy with and coloured it black at roughly 20 % opacity.
Here's the final object, after one more step: go to Effect > Stylize > Feather in your Illustrator menu (I suppose there are similar effects in other vector programs) and experiment a bit. This one was done using a 0.2 cm value, but that was necessary because of the overall scale of the entire project.
Finally, the (almost) complete intercooler details. You'll note that I added some grid lines or hull plate edges or whatever you want them to be - simply by placing a line on the object with a darker shade of grey and an opacity of 30 % or so (otherwise the line colour won't adjust to the colour below it). The last touch here was the fading shadow: a simple shape filled with a standard white/black gradient, using the Multiply option to filter out the white.
There's still more, so stay tuned.
(I really ought to spring for the upgrade, but I'm afraid that it won't run on my computer!)
(Note that I'm exhausting my technical vocabulary - which isn't that large to begin with, since English isn't my native language. I hope I can make myself understood).
Re: the line - is there no way to reduce an object's opacity in CorelDraw? Still, your solution is a good one and works just as well, I think.
I suppose you might enjoy a look at what lies beneath ...
And here, the outlines overlaid on the coloured image.
I hope this is helpful.