What is the difference between 3d surface modeling and solid moldeling?

[Anonymous]

What is the difference between 3d surface modeling and solid modeling in AutoCAD?

Thanks,

FT

[imadHabash]

Hi,

>> What is the difference between 3d surface modeling and solid modeling in AutoCAD? <<

breifly and in a very simple words :

 3d surface modeling is a thin shell that does not have mass or volume , which has the ability to convert to 3D modeling . 

Solid modeling is the method of creating geometric modeling in three dimensions.  

Regards, 

[leeminardi]

Check out this link:

https://forums.autodesk.com/t5/autocad-forum/solids-vs-surface-models/td-p/7337188

I would add to my comments that if you create a circle in AutoCAD and then extrude it the result will be an AutoCAD solid.  AutoCAD automatically adds the caps on the top and bottom of the cylindrical surface and defines the closed volume as a solid.  If you explode the solid you will have a surface model consisting of three surfaces, the two end cap surfaces and the cylindrical wall. 

AutoCAD surface models that define a "watertight" volume can be converted to a solid model with the surfsculpt command.  Note that AutoCAD will allow you to create what is considered an invalid solid that could contain multiple volumes that are not connected and solids with infinitesimally thin components.   For example, create a long cylinder and then subtract a box from its middle. The result is two cylinders that do not touch but AutoCAD will consider this a single solid object.  More robust solid modelers would not permit this result.