# Most Popular Iso Ratios?

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GroZZleR    820
What are the more common / popular Isometric perspective ratios? I know UO used 1:1. I'm fairly confident Fallout used a 2:1. I've also seen some 4:3s around, but I can't think of any commercial games as examples. I'm guessing the 2:1 and 4:3 are the more common.

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Activ8    130
Isometric Ratios

2:1 is probably the most pleasing to the eye and the easiest to program and the most commonly used.

Check out some of the old Ultima series of games. They vary from 1:1 (almost an overhead view) to a ratio that looks virtually like a 3D first person view, where you are not sure whether it is still isometric or not! Ultimately (no pun intended) it's up to you to decide what best suits the type and mood of game you are programming.

Regards

Activ8

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markr    1692
Technically the isometric projection stipulates that the angles are all 30 degress, which means that the ratio MUST be 2:1

Anything else changes it from isometric into some other projection (some of which must have names, but I don't know any of them).

Mark

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Activ8    130
Quote:
 Original post by markrTechnically the isometric projection stipulates that the angles are all 30 degress, which means that the ratio MUST be 2:1Anything else changes it from isometric into some other projection (some of which must have names, but I don't know any of them).Mark

Yes, Mark I agree, if you change the ratio to something other than 2:1 then by "definition" the projection is NO longer a "true" Isometric projection. "Of equal Length / Angle".

There is a simple maths formulae that can be used regarding offsetting of pixels to create various "Isometric Projections" and working out what their angles would be.

Formulae:(In it's simplest form)
Sum (add) the Ratio's together and then divide (/) them into 90% (Degrees), Then Multiply(*) the individual Ratios by the answer you get for the Division!

For example:

2:1 Ratio = (2+1) = 3 :
90%(Degrees) divided (/) 3 = 30%(Degrees).
Therefore angles for a 2:1 Ratio will be
(2x30)=60%(Degrees) and (1x30)=30%(Degrees) > Sum 90%(Degrees)

Table: Isometric Ratios.
1:1 = 45:45 (Degrees of Angle) > Sum 90%(Degrees)
2:1 = 60:30 (Degrees of Angle) > Sum 90%(Degrees)
3:1 = 67.5: 22.5 (Degrees of Angle) > Sum 90%(Degrees)
4:1 = 72:18 (Degrees of Angle) > Sum 90%(Degrees)
5:1 = 75:15 (Degrees of Angle) > Sum 90%(Degrees)
And so on.... And so on ....

Hope this helps

Activ8

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Guest Anonymous Poster
I'm pretty sure your formulas are wrong. The reason the 1:2 ratio is 30 degrees is that the sin of 30 degrees is 1/2. You can't just add the sides together.

For example, imagine you're looking straight down to a grid (90 degree angle). The height and width of a square tile would be equal. This is a 1:1 ratio, but you claim this occurs at a 45 degree angle!

A 45 degree angle should be 1: 0.707 (or 1: sqrt(2)/2).

For what it's worth, I always thought a 3:2 angle looks better than a 2:1 angle.

JSwing

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Activ8    130
Quote:
 Original post by Anonymous PosterI'm pretty sure your formulas are wrong. The reason the 1:2 ratio is 30 degrees is that the sin of 30 degrees is 1/2. You can't just add the sides together.

Bear in mind I have said that this formula is simply for working out what an approx angle would be for OFF SETTING pixel ratios to create an Iso Image.

It is NOT intended for use when used in a 3D Iso Engine using Arc Tans, Cos, and so on.

Activ8

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Drakkcon    612
Not to hyjack this thread, but I'd like to see the differences, any screenshots?

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Guest Anonymous Poster
projections which use ratios that are not 2:1 are known as axonometric projections. the 1:1 projection is known as dimetric (i think)