Rounded Rectangular Tray

// Linear tray 100x75x15 mm. Print flat, no supports. $fn=64; N=10; e=0.01; L=100; W=75; R=12; bt=5; wt=5; H=15; ri=R-wt; rt=2.4; ff=1; ch=0.6; module rr(l,w,r) offset(r=r) square([l-2*r,w-2*r],center=true); module sl(z,l,w,r) translate([0,0,z]) linear_extrude(e) rr(l,w,r); module outer() hull(){ sl(0,L-2*ch,W-2*ch,R-ch); sl(ch,L,W,R); for(k=[0:N]){a=90*k/N; d=rt*(1-cos(a)); sl(H-rt+rt*sin(a),L-2*d,W-2*d,R-d);} } module fl(k){a=90*k/N; d=rt*(1-cos(a)); sl(H-rt+rt*sin(a),L-2*wt+2*d,W-2*wt+2*d,ri+d);} module cav(){ hull(){ for(k=[0:N]){a=90*k/N; i=ff*(1-sin(a)); sl(bt+ff*(1-cos(a)),L-2*wt-2*i,W-2*wt-2*i,ri-i);} fl(0); } for(k=[0:N-1]) hull(){fl(k); fl(k+1);} hull(){fl(N); translate([0,0,1]) fl(N);} } difference(){ outer(); cav(); }

Parameters

Every value above is a live dimension. Open a model like this in the editor and each one becomes a slider you can drag before exporting.