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Ostentatio

Arched bridge weirdly asymmetrical

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Just planned a 1x6 arched marble bridge.

 

[20:58:54] looks like bridge would be 1x6 (North-South)

[20:59:19] Both ends are the same height, Nice!

 

Chose 20 slope.

 

There's no reason why the resulting bridge plan shouldn't look symmetrical, and yet...

 

wurm.20160213.2101_1.png

 

As you can see:

  • The first two bridge tiles from the left end are the same slope, but the first two tiles from the right end are not. Note that the right-hand abutment is significantly shallower in slope than the left-hand abutment.
  • The two middle tiles, consequently, are also not the same slope.

 

 

You would expect bridges to be symmetrical when possible, especially in a situation as simple as this, but apparently this is not always the case. Whatever calculates bridge slopes really ought to take this into account.

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Agreed, it is as if the slope is so hard coded that the rest/missing slope all ends up at one end.

I am planning on a long bridge atm also, and am worried the center part will look weird due to how this works.

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This bridge is totally symmetrical. The two floating sections on the left are fine, but the two on the right look like a tree fell across the bridge and flattened it out a bit:

 

 

E7OhIHH.jpg?1

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Did you take in account the length / elevation? I bet you missed that one Them sections are also based on length which determine which section gets used. if you would have made the bridge 1 tile longer it would of been or 1 tile shorter.

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17 minutes ago, Arkonick said:

Did you take in account the length / elevation? I bet you missed that one Them sections are also based on length which determine which section gets used. if you would have made the bridge 1 tile longer it would of been or 1 tile shorter.

 

If you mean mine, I specified that the bridge is the same height at each end. The type of bridge sections used are symmetrical, but the slope is not, even though it easily could be.

 

In Robbycrusoe's example, the same should apply, and even if the ends aren't the exact same height, that doesn't explain the bizarre dent on the right side.

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10 minutes ago, Ostentatio said:

 

If you mean mine, I specified that the bridge is the same height at each end. The type of bridge sections used are symmetrical, but the slope is not, even though it easily could be.

 

In Robbycrusoe's example, the same should apply, and even if the ends aren't the exact same height, that doesn't explain the bizarre dent on the right side.

You are forgetting length. Each bridge has several sections that are pre made in size. Based on the length and slope angle of the bridge there is a calculation which piece will fit and is placed. That's why I was saying if that bridge would have been 1 tile longer or 1 tile shorter it would have been equal fitting but it landed on a odd so it had to place which pieces will fit for that specific length.

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1 minute ago, Arkonick said:

You are forgetting length. Each bridge has several sections that are pre made in size. Based on the length and slope angle of the bridge there is a calculation which piece will fit and is placed. That's why I was saying if that bridge would have been 1 tile longer or 1 tile shorter it would have been equal fitting but it landed on a odd so it had to place which pieces will fit for that specific length.

 

... A bridge with an odd number of tiles is easier to make symmetrical. Assuming the bridge is the same elevation at each end, you just make sure the center tile at the apex of the bridge is flat, and then you have an equal number of tiles on either side of that, and making that symmetrical is easy. This is pretty simple, and is how the long arched stone bridge at my deed works... or seems to, anyway.

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Made a small video real quick showing about bridge and elevation. You need to count for the angle. The bridge will never come to a tee pee angle it will alwasy try to round it so you need to plan in a extra or 1 less tile when hitting arch's above 10. 

Hope this helps explain why you have what looks like a glitch in your bridge. It would be possible to make a new center piece which could take the place of this angle. As it stands the pieces we have this is the way it will be but maybe after this post they might make a new section to compensate for the higher arch's that's if they have time right now.

 

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You say it will be "round" on top instead of coming to a "teepee", but this is Wurm. Nothing is "round". Any arched bridge with an even number of tiles has to either have a zero-slope bridge section that doesn't lie in the middle, have two zero-slope sections that lie in the middle (since there is no one middle section in an even-length bridge), or will come to a point of some sort, somewhere, with the slope going down on either side. This last result is what actually happens. This also happens in the bridges in your video.

 

There's absolutely no reason why, in the example of my six-length bridge in the OP, the right side could not be an exact mirror of the left side. In fact, if it were, the "point" at the apex would actually be less severe!

 

Quick, dirty edit:

wurm.bridge-mirror.jpg

Or, mirror the other side:

wurm.bridge-mirror2.jpg

 

Either of these situations is better than the dang thing being asymmetrical. I would prefer the second example, since the arch's slope changes more gradually, but hey, better than having the slope be completely different on each side.

 

I'm also not sure what you mean by "which section gets used". It's an arched bridge, so everything but the abutments and bracings are the same section type; they're all floating.

 

How the developers think the game should choose how to pattern the slope on an arched bridge is to some degree arbitrary, but there is categorically no reason why it cannot be symmetrical if the bridge has the same elevation at each end.

If bridges actually needed there to be a flat tile toward the apex, I would understand your point about the bridge length being an issue, but clearly they don't, since every example in this thread has even-length arched bridges come to a point.

Edited by Ostentatio

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the issue stems more from how Wurm does a calculation

it allways calculates directional and not bidirectional, resulting in differences we can see above

 

OP screenies are directional, the "quick and dirty" screenies from Ostentatio are bidirectional

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