Oblique 3D Graphics - true or not?

[marenja]

Do these screens look like true Oblique 3D Graphics ? https://en.wikipedia.org/wiki/Oblique_projection
This one is something vice versa for me, i feel walls of this image as inverted and absolutely unreal. The world is like turning upside down. Or may be you are looking down but still the picture is not realistic.


List of all games with Oblique 3D Graphics https://spectrumcomputing.co.uk/list?group_id=11005
These are examples of good oblique 3d

Spoiler

But these from the same list look wrong.
These seem to be flat and you are looking down to the first one and the second is like a side view.

Spoiler

This looks like perspective projection.

Spoiler

This looks like 2d side view.

Spoiler

[Wall_Axe]

The later ultima games were like this.
Just thought I'd comment on the screenshots.

The Jetsons would look great if it had colour.
The game at the very top same comment.


That breakout game was terrible, but impressive programming

[AndyC]

They're all oblique projections, since none of them apply perspective. There's always a possibility with this that the end result can "look odd" because your brain can interpret the image in multiple ways and none of them are entirely correct.

[Einar Saukas]

This one is something vice versa for me, i feel walls of this image as inverted and absolutely unreal. The world is like turning upside down. Or may be you are looking down but still the picture is not realistic.

Yes, you are (kinda) looking down. The walls are correct. The problem is, everything else (including people) is supposed to be "inclined to the right" like the walls, they are not.

[Einar Saukas]

But these from the same list look wrong.

Agreed. The background view is top-down but the characters are sideways.

[Lethargeek]

List of all games with Oblique 3D Graphics https://spectrumcomputing.co.uk/list?group_id=11005

Spike in Transylvania is missing here
Pandemia is not oblique (and not even parallel)
also not sure if Survival ZX belongs here

They're all oblique projections, since none of them apply perspective.

Pandemia is fake perspective, and in any case is not oblique

Agreed. The background view is top-down but the characters are sideways.

and who said you can't have 2d characters moving on the ground in 3d world?

[Einar Saukas]

This looks like perspective projection.

All objects are oblique. Except each side of the screen has a different angle.

The last level of Renegade uses the same idea. However it doesn't look wrong because the side walls appear on separate screens, and graphics design is a million times better.

[Lethargeek]

All objects are oblique.

and the entire scene is not

[AndyC]

and the entire scene is not

Well it sort of is. There is no perspective (you can see the tiles on the walls are all parallel lines). It's just a really weird mash up of two oblique angles.

[Einar Saukas]

and who said you can't have 2d characters moving on the ground in 3d world?

Sure, almost every 3D game for the Spectrum have 2D characters. When done properly (like in Renegade) it looks great.

[sn3j]

This (top-down?) oblique projection was used in many games with RPG Maker, here Vampires Dawn.
As you see the characters are drawn from a side view but that still fits nicely.

[Lethargeek]

Well it sort of is.

no, it isn't - "oblique" belongs to "parallel" group where "parallel" means "all originally parallel lines remain parallel in the pic"
which is obviously not the case here (unless you want to believe the original angles were all meant to be so weird)

There is no perspective (you can see the tiles on the walls are all parallel lines). It's just a really weird mash up of two oblique angles.

that's why i'm calling it fake perspective (even better example is Kliatba Noci mixing 2d and (almost) true perspective 3d backgrounds)

[Einar Saukas]

This (top-down?) oblique projection was used in many games with RPG Maker, here Vampires Dawn.
As you see the characters are drawn from a side view but that still fits nicely.

I agree it looks nice. However that's not oblique or 3D. In ZXDB we call it Perpendicular 2.5D Graphics

[marenja]

Yes, you are (kinda) looking down. The walls are correct. The problem is, everything else (including people) is supposed to be "inclined to the right" like the walls, they are not.

DESOLATOR.
That picture looks like top-down oblique projection (see wiki). It is obviously not a military or cavalier oblique projection. But true top-down ob.prj has vertical lines for the front side (XZ is what you see, Z is STRICTLY vertical, X is from left to right, Y is depth). XZ plane should have `exact' proportions, it is a side view. This screen XZ is inclined and proportions LOOK like decreased. Probably they are not decreased if you measure them with pixel precise but they look like decreased.

Spoiler

[marenja]

PANDEMIA.

no, it isn't - "oblique" belongs to "parallel" group where "parallel" means "all originally parallel lines remain parallel in the pic"
which is obviously not the case here (unless you want to believe the original angles were all meant to be so weird)

AndyC wrote: ↑Sat Mar 09, 2024 2:44 pm
There is no perspective (you can see the tiles on the walls are all parallel lines). It's just a really weird mash up of two oblique angles.

that's why i'm calling it fake perspective

Fake perspective - that what exactly describes by feel of that screen. I think it is one-point perspective (see wiki) because all furniture lines should end in one point far away. "All objects will recede to points in the distance". https://en.wikipedia.org/wiki/Perspective_(graphical)

I think all lines do not run to single point just because of limitations in case of ZX graphics. So incorrect angle - constant 45 degrees - is just for simplification.

Spoiler

[AndyC]

PANDEMIA.


Fake perspective - that what exactly describes by feel of that screen. I think it is one-point perspective (see wiki) because all furniture lines should end in one point far away. "All objects will recede to points in the distance". https://en.wikipedia.org/wiki/Perspective_(graphical)

I think all lines do not run to single point just because of limitations in case of ZX graphics. So incorrect angle - constant 45 degrees - is just for simplification.

Look at the walls. Trace a line from the "horizontal" lines (the ones running diagonally up the screen) on each of the tiles. They are all parallel and will never ever meet at a vanishing point. That's no a limitation of ZX graphics, it's an oblique projection.

You can make the argument that since both halves of the screen use a different projection that the result isn't quite oblique, but it's not nearly close enough to perspective to call it "fake perspective" IMO. Maybe if objects further back had been drawn smaller or something.

[marenja]

Let us see user's case to seek for games. I know a cool game, e.g. renegade or double dragon and i am impressed with its graphics mode, that oblique 3d. I want to see other games that are like renegade and i click link "oblique 3d". But i see that `3d painter` and `pippo`. No. These games don't look like renegade, paperboy, back to future. They look like packman with shadows of the play field. Like shadows in `batty'. They don't only have bad sprites, they just dont feel to be that oblique 3d. The game `all or nothing' has poor graphics but it looks like oblique 3d.

Pippo is a sort of packman with some modifications. I believe 3d painter is a sort of packman too.

--
There can be ever worse case. A user sees '3d painter' and understands he knows a such games. Then he adds graphics mode oblique 3d for all those games and we have a bunch of packman games which are `oblique 3d`.

[marenja]

Look at the walls. Trace a line from the "horizontal" lines (the ones running diagonally up the screen) on each of the tiles. They are all parallel and will never ever meet at a vanishing point. That's no a limitation of ZX graphics, it's an oblique projection.

You can make the argument that since both halves of the screen use a different projection that the result isn't quite oblique, but it's not nearly close enough to perspective to call it "fake perspective" IMO. Maybe if objects further back had been drawn smaller or something.

Oblique projection is a type of parallel projection: ... lines of sight or projection lines, are parallel to each other.

I could see crossing lines (with some imagination). But i don't see lines at left side of screen are parallel to lines at right side. Wall lines are parallel, but they are at the borders and you are not focused on them. Furniture is in the center and furniture lines are crossing.

[AndyC]

Oblique projection is a type of parallel projection: ... lines of sight or projection lines, are parallel to each other.

I could see crossing lines (with some imagination). But i don't see lines at left side of screen are parallel to lines at right side. Wall lines are parallel, but they are at the borders and you are not focused on them. Furniture is in the center and furniture lines are crossing.

Put a piece of paper over the entire right hand side of the screen. Everything still visible on the left side is obviously oblique, all the lines are parallel. Now move the paper to the left hand side and observe the same is true of the right. Just because you then stitch the two together, it doesn't make any of it perspective.

Although, from a user accessing the database it's all moot anyway because nobody cares and none of these are strictly correct in any projection system. There are a slew of games we all call isometric, but they aren't. We'd be better off just going with "3D" as an over-arching term, "true 3D" for things like Freescape, "Pseudo-3D" for anything else and then terms like "isometric" for cases everyone can entirely agree upon.

[Einar Saukas]

Let us see user's case to seek for games. I know a cool game, e.g. renegade or double dragon and i am impressed with its graphics mode, that oblique 3d. I want to see other games that are like renegade and i click link "oblique 3d". But i see that `3d painter` and `pippo`. No.

That's like saying when you click "Arcade Game: Shoot-em-up" because you want to see other games that are like R-Type and Zynaps, but then you see Robot Panic.

It doesn't mean Robot Panic isn't "Arcade Game: Shoot-em-up", albeit a bad one.

Likewise oblique view not done properly is still oblique view.

[marenja]

That's like saying when you click "Arcade Game: Shoot-em-up"

Game genre is such a mystic category. You can see Repton has 'maze' genre, Lode runner is `platformer' and Parabola is `arcade action' but none of them is puzzle.

BTW can we add tag `puzzle`? So we can just assign this tag to such games and not to strike in holywars about game genres?

[Lethargeek]

Put a piece of paper over the entire right hand side of the screen. Everything still visible on the left side is obviously oblique, all the lines are parallel. Now move the paper to the left hand side and observe the same is true of the right. Just because you then stitch the two together, it doesn't make any of it perspective.

Why stop here? It's not like we're running out of paper! Let's cover all the "wrong" screen areas until we finally get something completely different! Like, why not cover everything except the back wall? Tadamm, now we see it's just a 2d game! Even better, why not cover everything except the string of letters? Tadamm, now we see it's just a text adventure!

Something existing won't disappear just because you refuse to look at it.

Let us see user's case to seek for games. I know a cool game, e.g. renegade or double dragon and i am impressed with its graphics mode, that oblique 3d. I want to see other games that are like renegade and i click link "oblique 3d". But i see that `3d painter` and `pippo`.

you're lucky you aren't offered the Beanstalk trilogy