Issue with engine exhaust positioning - Spearhead Interceptor

For test results, bug reports, announcements of new builds etc.

Moderators: another_commander, winston, Getafix

Rendell001
Average
Average
Posts: 12
Joined: Sun Aug 23, 2020 2:34 pm

Issue with engine exhaust positioning - Spearhead Interceptor

Post by Rendell001 »

Hi there, I wonder if you can help me, back in 2006 when I first discovered Oolite I decided to have a go at designing my own ship.
Considering I was a complete newbie (still am) I was quite pleased with the result... except no matter what I did, I couldn't seem to fix the positioning of the engine exhausts - they were always a dozen metres away flying in formation with the ship!

I'd really like to fix this and maybe even update the texture but as I said, I'm a complete beginner.

Any help or advice you could give me would be deeply appreciated.
User avatar
cbr
---- E L I T E ----
---- E L I T E ----
Posts: 1377
Joined: Thu Aug 27, 2015 4:24 pm

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by cbr »

This is for the exhaust plume positions.

http://wiki.alioth.net/index.php/Shipdata.plist#exhaust

Or if your ship contains separate (engine)models first 3 variables are x y z next 4 rotation

subentities = (
"engine 0 0 0 1 0 0 0",
"engine 0 7 0 1 0 0 0",
"engine 6 3.5 0 1 0 0 0",
"engine -6 3.5 0 1 0 0 0",
"command 0 0 0 1 0 0 0",
"sempod 0 0 0 1 0 0 0",
"sempod 0 0 -50 1 0 0 0",
"spinepod 0 0 0 1 0 0 0",
"landingpod 0 0 0 1 0 0 0",
"landingpod 0 0 -48 1 0 0 0",
"landingpod -26 0 -48 1 0 0 0",
"landingpod -26 0 0 1 0 0 0");

If your are able to obtain the coordinates of your shipmodel then you will be able to use these to position both kind of exhausts,

but it ( for the models.dat ) also depends on their own offset from x y z ( are they centered or not ).

And I also use the gallery.oxp to look for better repositioning of entities
Rendell001
Average
Average
Posts: 12
Joined: Sun Aug 23, 2020 2:34 pm

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by Rendell001 »

Firstly, many thanks for your rapid response.

Currently, the exhaust info from the Plist looks like this:

<key>exhaust</key>
<array>
<string>0.406 16.437 32.094 0.25 2.0 6.0</string>
<string>3 14 29.969 1.0 0.35 3.0</string>
<string>-2 14 29.969 1.0 0.35 3.0</string>
<string>5.531 14 29.969 1.0 0.35 3.0</string>
<string>-4.531 14 29.969 1.0 0.35 3.0</string>

The design of the ship model is a little awkward at the back for exhaust placement - four sub thrusters mounted on the underside and a main engine mounted centrally above them.

I'll dig up a couple of screenshots to show how far out they are...
User avatar
montana05
---- E L I T E ----
---- E L I T E ----
Posts: 1166
Joined: Mon May 30, 2016 3:54 am
Location: lurking in The Devils Triangle (G1)

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by montana05 »

Rendell001 wrote: Sun Aug 23, 2020 5:48 pm
I'll dig up a couple of screenshots to show how far out they are...
Screenshots certainly will help but to offer useful assistance the model (and therefore the dimensions) would be a better place to start. :)
Scars remind us where we've been. They don't have to dictate where we're going.
Rendell001
Average
Average
Posts: 12
Joined: Sun Aug 23, 2020 2:34 pm

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by Rendell001 »

Hi, sorry for the late reply, I've uploaded links for the ship model and it's plist.

The model was originally constructed in an early version of Wings3d - I suspect this might be a problem in 2020.

Spearhead model Dat file:
http://s000.tinyupload.com/index.php?fi ... 5264523499

Ship data plist:
http://s000.tinyupload.com/?file_id=099 ... 7974449829
Rendell001
Average
Average
Posts: 12
Joined: Sun Aug 23, 2020 2:34 pm

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by Rendell001 »

Here are the screenshots to show you what I mean:

Image Image
User avatar
cbr
---- E L I T E ----
---- E L I T E ----
Posts: 1377
Joined: Thu Aug 27, 2015 4:24 pm

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by cbr »

The first screenshot shows the exhaust to be far behind ( which should be x y z, the third coordinate )
The second screenshot shows the exhausts to above and beyond eh in front ( that's really odd )

Does the model appears as it should be in the new versions of oolite or does it have errors?

I noticed some really old models showing errors because of the way they were build/converted.
Rendell001
Average
Average
Posts: 12
Joined: Sun Aug 23, 2020 2:34 pm

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by Rendell001 »

Actually, these screens were taken from the latest version of Oolite - 1.88.

I'm afraid the exhausts have always been an issue on this model but the rest of it appears in game as it was meant to be.

I will update the textures to something more in keeping with the newer ships.
User avatar
montana05
---- E L I T E ----
---- E L I T E ----
Posts: 1166
Joined: Mon May 30, 2016 3:54 am
Location: lurking in The Devils Triangle (G1)

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by montana05 »

Rendell001 wrote: Tue Aug 25, 2020 1:23 am
I'm afraid the exhausts have always been an issue on this model but the rest of it appears in game as it was meant to be.
If you could provide me with a model in .dat and any simple texture I could have a look at it.
Scars remind us where we've been. They don't have to dictate where we're going.
Rendell001
Average
Average
Posts: 12
Joined: Sun Aug 23, 2020 2:34 pm

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by Rendell001 »

Hi there, I posted a link to the .dat file and plist in the post before the screenshots - did they not link properly?
Rendell001
Average
Average
Posts: 12
Joined: Sun Aug 23, 2020 2:34 pm

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by Rendell001 »

I've gone with another file host just in case:

https://www.filehosting.org/file/detail ... head_1.dat
User avatar
montana05
---- E L I T E ----
---- E L I T E ----
Posts: 1166
Joined: Mon May 30, 2016 3:54 am
Location: lurking in The Devils Triangle (G1)

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by montana05 »

Rendell001 wrote: Wed Aug 26, 2020 3:07 pm
Hi there, I posted a link to the .dat file and plist in the post before the screenshots - did they not link properly?
Sorry, my bad, I didn't see your link. :oops: I will have a look at the weekend, probably re-assign your exhausts. :wink:
Scars remind us where we've been. They don't have to dictate where we're going.
Rendell001
Average
Average
Posts: 12
Joined: Sun Aug 23, 2020 2:34 pm

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by Rendell001 »

Hi there, just wondered if you'd been able to have a look at that .dat file and see if you could spot the problem?
User avatar
cbr
---- E L I T E ----
---- E L I T E ----
Posts: 1377
Joined: Thu Aug 27, 2015 4:24 pm

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by cbr »

I looked at the data from your .dat

De cube is for center reference

Image

The top measures about 5

You used 16 and 14 for the y-position of the exhaust
<key>exhaust</key>
<array>
<string>0.406 16.437 32.094 0.25 2.0 6.0</string>
<string>3 14 29.969 1.0 0.35 3.0</string>
<string>-2 14 29.969 1.0 0.35 3.0</string>
<string>5.531 14 29.969 1.0 0.35 3.0</string>
<string>-4.531 14 29.969 1.0 0.35 3.0</string>
The tip of your spaceship is about 21

You used 29 and 32 for the z-position of the exhaust, which put them in front of the ship?

Image

Try something like this and see if it makes a difference in the right direction
<key>exhaust</key>


<array>
<string>0.406 2 -2 0.25 2.0 6.0</string>
<string>3 0 -4 1.0 0.35 3.0</string>
<string>-2 0 -4 1.0 0.35 3.0</string>
<string>5.531 0 -4 1.0 0.35 3.0</string>
<string>-4.531 0 -4 1.0 0.35 3.0</string
:)
Rendell001
Average
Average
Posts: 12
Joined: Sun Aug 23, 2020 2:34 pm

Re: Issue with engine exhaust positioning - Spearhead Interceptor

Post by Rendell001 »

Thats terrific, thank you for doing this, this gives me something to go on - I don't know how I got the initial values so wide of the mark.

Incidentally, what program did you use to check the model?
Post Reply