Trying to use the ExtrudeCrv command to create a solid object but it just extrudes as a hollow crv (Picture Below). The ‘solid’ option on ExtrudeCrv is also on. Please suggest what can be done
Quick thought that you probably check but are all curves closed that you want to extrude?
some of them are open curves but when i run the closecrv command, it just connects them randomly and not according to the shape/boundary. Is there any way to manually close the curve in a way i want?
You are going to need to do this on an individual curve-by-curve basis, join the various segments the way you want and draw your own curve to close if necessary.
Alternatively, select all the curves and use CurveBoolean (DeleteInput=All) and then pick all the closed regions you want to be able to extrude after. If you can’t select a particular region, it means there is a gap somewhere.
And to add to @Astrid_Kjærbølling’s comment, also make sure that they are all at the same level (eg. by using ProjectToCplane in the top viewport). Otherwise they will extrude as separate entities.
HTH, Jakob
yes i have put them all on the cplane
how can i know where the gaps are so i can close them?
You can use the command CrvStart or CrvEnd to get the start point or end point of a curve
SelClosedCrv and SelOpenCrv are also of use 
-Jakob
Each curve needs to be a separate single closed curve or polycurve for the extrusion to create a solid.
Upload a .3dm file with the curves if you need more information.