Watch The Video For the Full Experience!
I made a video tutorial about this topic, and I really suggest watching the video as it goes in depth and shows lots of examples! https://youtu.be/q-adA4Qzdk0
If you can't though, I've provided most of the information in this article as well.
What IS perspective?
We humans live in a 3D universe. BUT, when we draw, we are working in 2D.
What's the difference then?
Here is a wooden toy block. In real life, it has edges that are going the exact same way, that's called parallel.
I like to think, if edges are parallel, then they are partners!
Here's what's REALLY important to understand.
They're only parallel in real life.
When I turned the block, in my REAL LIFE, they were, of course, still parallel.
but in this 2D IMAGE, the edge lines are NOT parallel anymore. They are getting closer together the farther away they get.
If you continue to draw their directions, eventually they will go to the same point.
One More Thing To Remember: HORIZON LINE (also known as EYELINE)
The horizon, or eyeline, is the height at which the camera of the picture is at.
Stuff that's at the level of the horizon, we would be looking STRAIGHT at.
Anything below the horizon, we're looking down on.
Anything above, we're looking up on.
This is easy to remember because we look UP at the sky, and DOWN at the ground.
Here I made a column of thin rectangles. As we can see we look down at the ones below, and up on the rectangles above.
DOES THAT APPLY TO CHARACTERS?
YES! Even if you're drawing a character floating in a white void, you should remember this and apply it. It will make your drawings look much more solid!
In fact, I forgot about this for years. Here's what my art looked like before and after applying it!
PERSPECTIVE RULER IN CLIP STUDIO
To make a perspective ruler go to the top menu.
Layer -> Ruler Frame -> Create Perspective Ruler
Then a popup will come up with the options of 1, 2, or 3 point perspective.
If you are confused on what to pick, I recommend just always choosing 3 point.
Lines will appear on your canvas. The blue line, is the horizon line. The purple lines are lines that are going to a vanishing point! With 3 point perspective, 2 vanishing points are on the horizon line, and the last vanishing point is above the canvas.
To adjust any of the rulers in our perspective ruler we need to have the OPERATION OBJECT TOOL selected.
Now if you select the blue horizon line, we now see a lot of dots appear.
With the object tool, we can select these dots and manipulate our ruler!
You can move the horizon line up or down. And you can select the vanishing points to move them!
WHY ARE SOME VANSHING POINTS ON THE HORIZON? DO THEY HAVE TO STAY THERE?
Your house floor, is most likely parallel to the ground right?
Aside from slanted houses on hills, MOST all houses and buildings are parallel to the ground.
The ground is visible ALL the way to the horizon line. SO, if a vanishing point is ON the horizon line, that means it is for lines in your scene that are parallel with the ground. Luckily that IS the case for almost all buildings!
WHY IS ONE VANISHING POINT ABOVE? CAN I MOVE IT?
The vanshing point above, is for vertical lines in our scene! Houses and buildings also have the walls that go up! And that vanishing point is for them.
HOWEVER, wether this vanishing point is above or below the horizon line MATTERS!
When it's ABOVE the horizon, that's for drawing things ABOVE the horizon!
When it's BELOW the horizon, that's for drawing things BELOW the horizon.
If you have this vanshing point in the opposite position it should be, the ruler will make you draw odd looking boxes that are wider at one side, like a gold ingot. (as you can see in the following image)
The next image, shows a proper box, with the 3rd vanishing point BELOW the horizon, because we are looking down on the box.
ADDING AND DELETING VANISHING POINTS
Sometimes you need more than 3 vanishing points!
To add more, go to:
Ruler Tool -> Perspective Ruler -> Properties Panel -> Add Vanishing Point
Then click on your canvas a couple times to set up where the lines should be.
(Don't worry about setting it in the right spot, because you can move it after with the object tool)
To delete a vanishing point, simply right click it with the object tool and select delete.
THE RULER ISN'T WORKING ANYMORE!!! (DISABLING / ENABLING VANISHING POINTS)
I ran into this problem myself. It's possible to accidentally disable a vanishing point.
Check out the color of the vanishing points lines. Purple means on. Green means off.
To turn it on or off, simply hit the little diamond shown in the image.
ADDING A 3D FLOORSPACE
Let me show you a cool trick.
Go to Top Menu - Layer -> New Layer -> 3D Layer
Now on your canvas is a 3D floor! But also our perspective ruler isn't visible anymore, lets fix that.
On our new 3D floor layer it has a red X on it.
Click the red X. (or right click -> Show Ruler)
Now we can see that new 3D layer AND it's aligned to your perspective ruler!
And that's it! Hope this helped you out!
My last tip, is to not think of perpsective as something that only applies to buildings.
Perspective is HOW we see the world, and it applies to everything! Even characters!
So don't forget it. Happy drawing!