here are a few ideas for other new symbols.

I am extensively using a few additional symbols while drawing projections: dashed contours for contours thare are on the back-side of the projection, dashed areas for the connection of two galleries or for a void / gallery orthogonal to the projection.

I am also using an additional line symbol (which should be actually clipped off automatically) for the direction of fractures visible on the walls, and I am often missing a point symbol "dip" for the inclination of the strata

Xavier

## To draw contours which are on the back-side of the projection
def l_u_backcontour (expr Path) =
    T:=identity;
    pickup PenD;
    draw Path dashed evenly scaled (0.25 * optical_zoom);
enddef;

## Area of connection of two galleries, orthogonal to the projection and on the front-size
def a_u_connection(expr Path) =
#% density
numeric dx; dx := 0.25u;
T:=identity;
path q; q := bbox Path;
numeric lq; lq :=   xpart urcorner q - xpart llcorner q;
numeric hq; hq :=   ypart urcorner q - ypart llcorner q;
numeric dq; dq := lq+hq;
picture tmp_pic;
tmp_pic := image(
    for i = xpart llcorner q - hq step dx until xpart urcorner q:
      numeric j; j := ypart llcorner q;
      thdraw (i,j)--(i+hq,j+hq) withpen pensquare scaled (0.01u);
    endfor;
);
clip tmp_pic to Path;
clip tmp_pic to Path shifted (-dq/40,-dq/40);
draw tmp_pic;
enddef;
# initsymbol("a_u_connection");

## same for connections on the back-side of the projection
def a_u_backconnection(expr Path) =
#% density
numeric dx; dx := 0.25u;
T:=identity;
path q; q := bbox Path;
numeric lq; lq :=   xpart urcorner q - xpart llcorner q;
numeric hq; hq :=   ypart urcorner q - ypart llcorner q;
numeric dq; dq := lq+hq;
picture tmp_pic;
tmp_pic := image(
    for i = xpart llcorner q - hq step dx until xpart urcorner q:
      numeric j; j := ypart llcorner q;
      draw (i,j)--(i+hq,j+hq) dashed evenly scaled (0.5 * optical_zoom) ;
    endfor;
);
clip tmp_pic to Path;
clip tmp_pic to Path shifted (-dq/40,-dq/40);
draw tmp_pic;
enddef;
endcode

def l_u_fracture (expr P) =
    T:=identity;
    cas := 0;
    dlzka := arclength P;
    mojkrok:=adjust_step(dlzka, 0.8u);
    pickup PenC;
    k := 90;
    forever:
      t1 := arctime (cas + mojkrok*1/5) of P;
      t := arctime (cas + mojkrok/2) of P;
      t2 := arctime (cas + mojkrok*4/5) of P;
      thdraw (subpath (t1,t2) of P);
      mark_alt (P,t,0.2u, k);
      cas := cas + mojkrok;
      k := (k + 180) mod 360;
      exitif cas > dlzka - (2*mojkrok/3); % for rounding errors
    endfor;
enddef;
initsymbol("l_fracture_XAV");

Le 11/11/2011 20:48, Stacho Mudrak a écrit :

Hello everybody,

after drawing a complex map of one show cave, I would like to add new standard symbols to therion. These should include:

line edge - should be used to draw other then rock edges, e.g. wall structures in elevation. There is already rock-border -- rock-edge pair, there is general border symbol but no general edge symbol.

line rope - already discussed here, just line point option anchor on|off should work also

line handrail - this symbol already exists in some cave symbol sets. A line with dots in plan, in elevation some standard 1m tall handrail would be drawn.

point handrail - used to draw handrail in cross-sections

line steps - should be used in both, plan / elevation projections. In plan, this line would surround steps area and steps would be drawn parallel to the first line segment. In elevation, 20cm steps would be drawn.

line path - used to draw concrete or other path in caves, where it was built. If it will be closed curve, it will be filled with "area path". See below.

area path - fill for path areas. It would be automatically applied for closed line steps/path in plan projection.

Also should be added:

line rope-ladder

line fixed-ladder

line via-ferrata

point via-ferrata

Do these symbols make sense? Any comments? Any other symbols, that should exist in the standard therion library?

Thanks a lot for the feedback, S.
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