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Cessna 177 Development

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Cessna 177 Development

Postby openflight » Mon Jun 10, 2019 7:18 am

The Cessna 177 is not offered in the current list of FG aircraft, nor is it in the repository. A sleek looking aircraft, I search for "Cessna 177 Flight Gear" yielded such model, within the archive of a flight gear installation. Looking into this further, I found a model situated within the "AI" folder of a newer (3+) FG distribution.

Here is the model imported in its current form into Flight Gear, at my Flight Gear One website.

https://sites.google.com/site/flightgea ... cessna-177

Image
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Re: Cessna 177 Development

Postby openflight » Mon Jun 10, 2019 10:37 am

Opened the c177.ac file in Blender (Win 32, version 2.49b). This version has some added features that will be useful in importing and exporting files.

Exported the model to .3ds so it can be opened in Wings 3D

Imported the model into Wings 3D (Version 1.54, Ubuntu 16.10)

Copied the file into the Models folder (right now I am using a copy of the Cessna 172 folder for the moment)

Modified the xml file inside the model folder called c172p.xml as follows

<PropertyList>

<path>c177.3ds</path>

The 3ds file loads into FG, but without animations, textures, and the airplane is floating in the air.

Also the cockpit floor is now transparent as well as the windscreen. How to fix this?

https://sites.google.com/site/flightgea ... cessna-177
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Re: Cessna 177 Development

Postby openflight » Tue Jun 11, 2019 6:33 am

Apparently it has to do with normals on the surfaces and double vs single surfaces:

http://wiki.flightgear.org/Normals_and_ ... y_Tutorial
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Re: Cessna 177 Development

Postby CaptB » Tue Jun 11, 2019 6:42 am

Post your model's file somewhere so that we can look at it and maybe point out what may be the problem.
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Re: Cessna 177 Development

Postby openflight » Wed Jun 12, 2019 1:52 am

Well thanks. I was wondering if I create the cabin area separately and insert it into the cabin area of the model like a model plastic kit will it solve the problem?

Actually its the stock c177 found in the AI folder, converted using Blender from .ac to .3ds and then edited with Wings 3D to make the cockpit transparent.

Also, the model is suspended in the air, although centred in the WIngs 3D editor.
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Re: Cessna 177 Development

Postby CaptB » Wed Jun 12, 2019 5:05 am

openflight wrote in Wed Jun 12, 2019 1:52 am:Actually its the stock c177 found in the AI folder, converted using Blender from .ac to .3ds and then edited with Wings 3D to make the cockpit transparent.


Well, obviously you have the normals pointing out, so when you made the transparent area you exposed the backside of those faces and they won't render from that side. You need to solidify parts of the mesh that you want to be visible or just make a simple cockpit. another option is to make the faces(normals) double sided but you will have a performance hit.

Also, the model is suspended in the air, although centred in the WIngs 3D editor.


You're using the XML files for a different model, a C172. You have to change the values to work with your model.
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Re: Cessna 177 Development

Postby openflight » Wed Jun 12, 2019 5:27 am

Simple cockpit/cabin it is. Do some aircraft use this approach? Many models just seem to use the inside of the model with transparent panels.

I tried the position settings but they don't seem to work. Just to clarify: this file:

FlightGear/data/Aircraft/c172p/Models/c172p.xml


Change the z-coordinate?

<PropertyList>
<path>my-cessna.ac</path>
<offsets>
<pitch-deg>0</pitch-deg>
<heading-deg>270</heading-deg>
<roll-deg>0</roll-deg>
<x-m>0</x-m>
<y-m>0</y-m>
<z-m>-1.5</z-m>
</offsets>
</PropertyList>

Reference: http://wiki.flightgear.org/Howto:3D_Aircraft_Models
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Re: Cessna 177 Development

Postby CaptB » Wed Jun 12, 2019 6:34 am

openflight wrote in Wed Jun 12, 2019 5:27 am:
Change the z-coordinate?


I'd start there, yes.

<z-m>-1.5</z-m>


This.
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Re: Cessna 177 Development

Postby openflight » Fri Jun 14, 2019 2:08 am

The cabin area 3D file geometry is not set up to create the windows and window pillars without modification. I have separated the cabin area from the rest of the aircraft model and I will have to build the aircraft cabin separately.

The cabin seems to be slightly curved at the top, and very much curved at the bottom.

https://upload.wikimedia.org/wikipedia/ ... alRG01.jpg

First thing is to build a square cabin and check against the real thing. There must a be sequence to create the cabin - floor, then seats, then doors and then sides? What do people use?
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Re: Cessna 177 Development

Postby wkitty42 » Fri Jun 14, 2019 4:01 pm

i think some make a box and then trim/shape it to fit... from what i've seen, seats are last or nearly so... so box, dashboard/control panel, doors, instruments with yoke and pedals, and then seats... but don't take that as gospel... i'm only an observer when it comes to 3D stuffings...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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