[x3d-public] Problem with inverted polygons/normals

[Roy Walmsley]

Hi Don,

I had a look at that model in my Coin3D based viewer. It definitely had problems. I modified the X3D file, changing all nine instances of the "solid" attribute from 'false' to 'true'. It looked a lot better then, but still has some problems. When I moved the model in Examine mode it would change at very specific angles. This suggests to me that, at least in my implementation, which is by no means complete, I am seeing Z-fighting issues. Is it perhaps changing the drawing order depending on the angle?

I did try changing "ccw" to 'false' for the facial geometry shape. It made it look worse, so I don't think that is the problem. I changed it back after that.

I captured a short video - sorry about the quality - to indicate the effect. It's attached.

Roy

-----Original Message-----
From: x3d-public [mailto:x3d-public-bounces at web3d.org] On Behalf Of Don Brutzman
Sent: 07 November 2017 15:17
To: X3D Graphics public mailing list <x3d-public at web3d.org>
Cc: Mario Nagamura <mnagamur at lsi.usp.br>; support at okino.com; Barb Helfer <dir-communications at SIGGRAPH.ORG>; Andreas Plesch <andreasplesch at gmail.com>
Subject: [x3d-public] Problem with inverted polygons/normals

Initial draft version of an interesting new model is available at

	Shay D Pixel Version 2
	http://x3dgraphics.com/examples/X3dForAdvancedModeling/ShayDPixel/ShayDPixelVersion2Index.html

This version was exported from an .fbx version using Okino Nugraf.  Original at

	http://x3dgraphics.com/examples/X3dForAdvancedModeling/ShayDPixel/pixel_v2.fbx

It looks OK in several players (such as Instant Reality and X3DOM) but polygon ordering appears reversed in X_ITE.  Adjusting the solid field hasn't helped.  Perhaps a normal issue?

Wondering if anyone else can figure out what is going on here, screenshot attached for clarity.  TIA for all help.

all the best, Don
-- 
Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman
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