Solids - Silhouette - Wrong side

[ameurdefroid]

Hello, I am using the solids library and I thank the authors. However, I noticed an error in the projection of an edge.This MWE to explain

triple eye = (1,1,1) ;
triple up = (0,1,0) ;

currentprojection = orthographic(eye, up, O) ;
currentlight = nolight;

// ko
triple direction = (0, -1, 0) ;
// ok
//triple direction = (0, 1, 0) ;

triple cdc = (0,0,-1) ; 
triple Zlocal = unit(cross(cdc, direction)) ;

triple P1 =  -(0.3)*Zlocal- 1/2*direction ;

revolution rExt = revolution(O, P1 -- P1+1*direction, direction, angle1 = 180, angle2 = 360) ;
draw (rExt.silhouette(), red+0.05) ;
draw (surface(rExt), lightblue) ;

When the direction is (0,-1,0), a wrong edge appears while the contour is correct for (0,1,0).

Thanks for your feedback. AM

[johncbowman]

Since the silhouette routine is intended only for 2d projections, you need to add these two lines at the beginning of your example:

import solids;
settings.render=0;

As stated in solids.asy, this routine returns an approximate silhouette and is only indended for 2D projections. I'm not even sure what the desired silhouette should look like for this example. It's probably better to draw it by hand, using knowledge specific to the given object.