[Solved!] Surface Normals

23 Apr 2013 18:57 - 29 Apr 2013 02:01 #8845 by Vodoun da Vinci
I have an aircraft model that when I look at it from the outside it is fine but when I look out from inside some surfaces are invisible. Specifically, I can look right thru the floor of the cockpit but when viewed externally I simply see the surface of the fuselage. :S

Stuart introduced me to the concept of "Normals" and walked me thru the possibility of modifying them via AC3D. I had a look see at the menus and such but the agenda this evening/this week is to solve that issue and move along.

Any insight, theoretical or practical, on this subject would be greatly relished and appreciated. :)

Thanks in advance!

VooDoo

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23 Apr 2013 23:20 #8846 by Algernon
If, as I think in this case, it's an aircraft where the only internal view is cockpit view, you would usually use a cockpit tub, with normals facing outwards on all three directions, tucked inside the fuselage. With your VooDoo Dolls, they already have pretty nice cockpits which you don't really want to intrude upon, so I would suggest you need to "skin" the problem area somehow.

I can suggest a rough and ready way of fixing this, but there are more experienced modellers around here who could probably give better advice than me, so I'm going to hold onto it for now. The cockpit floor, though, shouldn't be too difficult a one to fix.

That's not a lot of help, but if nobody else has better suggestions, I'll post a quick fix to put in a basic flat floor and try to retain any texturing. Which model is it, by the way?

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24 Apr 2013 01:02 #8847 by Vodoun da Vinci
I appreciate the help and there is no hurry... :)

It's the 'Spit Vb and there are quite a few surfaces that are acting a little "odd" where you can see some of the bit in some views but none of it in another view. I have been playing with it quite a lot and, unfortunately, I'm under the impression it needs binned. :pinch:

I spent a couple hours on it this evening and I'm under the impression it is unresolvable by me at this point in my learning curve. I can't afford to cease forward motion on this one sticking point and I have to abandon the model if I can't resolve it.

Sad but true...I have exhausted my resources and I'm moving on to other problems to be fixed in the P-51 Mustang III and Focke Wulf FW-190. Hopefully I'll learn something applicable but for now this awesome example is binned. :(

VooDoo

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24 Apr 2013 13:12 #8861 by Vodoun da Vinci
OK, not binned....I "archived" it and I'll return to it when I get further along. ;)

I think the best bet is to nick a tub and size/configure it to this model and drop it into the cockpit area and stretch and size it to fit.

Tried everything else to fix the transparency issues/surface normals but struck out.

Moving along now but if anyone has advice or perspective I'd love to have it.

VooDoo

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25 Apr 2013 20:16 #8892 by Vodoun da Vinci
Just thinking out loud....installing a tub to block the view out the bottom of the fuselage solves that issue but I have other "semitransparent" bits like in the windscreen that come and go depending on the angle viewing thru them.

Damn.

VooDoo

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26 Apr 2013 09:25 #8902 by Algernon
The windscreen frame or the glass? Glass is a tricky thing to get right, I found, but didn't take me long to solve. If the frame is coming in and out at different angles, that's probably another matter...

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26 Apr 2013 10:37 #8903 by dfaber

Vodoun da Vinci wrote: Just thinking out loud....installing a tub to block the view out the bottom of the fuselage solves that issue but I have other "semitransparent" bits like in the windscreen that come and go depending on the angle viewing thru them.


semitransparent and flashing can be due to transparency (alpha) in the texture image. In the early years partially transparent images were used to e.g. cut holes in instrument faces.
Nowadays this is done by cutting the mesh or use transparent Material. It's generally better to avoid alpha in Textures. Mixing both methods can lead to Z Buffer fighting (flashing), as well as duplicate faces with normals in the same direction.

Greetings

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26 Apr 2013 11:23 #8904 by Vodoun da Vinci
Thank you, Detlef. We/I have encountered this "alpha channel" problem with various aircraft and solved it by turning the texture files into .jpg which don't support alpha channels. :)

It's have been easier probably to just delete the alpha channel within the .png but I've not managed to figure out how to accomplish that via Photoshop or Gimp. :oops:

Algy, it's the frame that is partially visible and angle dependent. I'm pretty sure it is of the same cause as the invisible floor when viewed from one angle but not the other.

I can see the normal and reverse them in AC3D but have not been able to make the normal "double sided"....I may have to break down and configure Blender and go at it from that aspect but the idea of spending hours and hours trying to get Blender to where I can make it go literally puts me in a frame of mind where I can't function and curiosity and reverse engineering passion rapidly degrade into despair and makes me wanna just chuck the whole project.

I might have to just leave it lay for a few weeks until I gain more momentum via success in other areas.

Is there such a thing as "Blender Light" or "Blender Quick Start"?

:lol:

VooDoo

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26 Apr 2013 12:12 #8905 by thebroons
@ VooDoo

It's have been easier probably to just delete the alpha channel within the .png but I've not managed to figure out how to accomplish that via Photoshop or Gimp.


I can do that. Mac OS X versions use Preview, and removal of alpha is an option when saving PNGs. Like you, still don't know how it's done in PS / Gimp. :blush:

But if I figger it out, Imma gonna tell ya!

G

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26 Apr 2013 12:15 #8906 by Vodoun da Vinci
Curious minds wanna know... :lol:

I'd be content with conversion to .jpg but it does not support transparencies like .png.

VooDoo

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26 Apr 2013 12:20 #8907 by thebroons

Curious minds wanna know...


They don't get much more curiouser!!! :P :silly: :lol: :woohoo:

Of course, during the course of my response, my own curious nature evolved it further...

"Captain Curious", then a band name "Capt. Curious and the Confusioneers"

Gad I'm a sick one.... :woohoo: :side:

G

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26 Apr 2013 13:11 #8908 by thebroons
Update:

For PS, go to (main menubar) Windows ->Channels then delete alpha channel (will only be on layers with transparency)

For GIMP,

7.34. Remove Alpha Channel

This command removes the Alpha channel of the active layer, keeping the Apha channels of the other layers.

If the active layer is the background layer and if you have not added an Alpha channel before (then the layer name is in bold letters in the Layer Dialog), the command is grayed out, inactive.

If the active layer is not the background layer, transparency is replaced with the background color of the Toolbox.

7.34.1. Activate the Command
You can access this command from the image menubar through Layer → Transparency → Remove Alpha Channel.

In addition, at the Layer Dialog, you can access it through Remove Alpha Channel of its context pop-up menu.

Hope this helps!


G

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26 Apr 2013 13:12 #8909 by Vodoun da Vinci
I'll have a look when I get home tonight!! :)

VooDoo

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29 Apr 2013 00:32 - 29 Apr 2013 02:04 #8951 by Vodoun da Vinci
This issue is resolved and the Spitfire VB_VooDoo is back on track!! :woohoo: :cheer:

It did indeed end up being an issue with normals and making them 2 sided in AC3D fixed the issues with both seeing thru the underside of the model thru the cockpit as well as the windscreen and canopy issues.

This one really is drop dead gorgeous and the animations are progressing as well. Look for a developers release of this 'Bird and the MustangIII_VooDoo this week if time permits.

They are far enough along to be allowed to be seen and tested by other developers.

If someone wants details on the solution send me a PM. Proper credit goes to Stuart for walking me thru the procedures and possibilities and without his help I'd not have fixed this and moved along.

One more tool in the Bag-O-Tricks.... :cheer:

VooDoo

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29 Apr 2013 03:21 #8954 by Algernon
Fantastic! Get a copy uploaded, and I'll help turn those lovely sounds I heard earlier on the TV channel into MP sound awesomeness :) Don't think we've got an MP sound enabled warbird yet, have we?

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29 Apr 2013 07:16 #8957 by helijah
Hi VooDoo

This is one of the biggest problems I encounter since I try to explain why I did certain things and not others.

I have explained some basics here (but in French) embaranger.free.fr/viewtopic.php ? Explanation of 3D (in French)

Regards Emmanuel

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29 Apr 2013 11:27 #8961 by Vodoun da Vinci
I need all the help I can get...Thank You, Emmanuel! :)

VooDoo

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