1. A computer implemented method for manipulating a terrain in a drawing comprising: (a) obtaining, in a computer-aided design (CAD) building information modeling (BIM) application, a composite object of the terrain, wherein: (i) the composite object comprises a combination of two or more sub-objects; (ii) each of the two or more sub-objects defines a geometry that is part of the terrain; (iii) each of the two or more sub-objects is a result of an operation; and (iv) the two or more sub-objects are arranged in a system of dependent relationships; (b) drawing each of the two or more sub-objects on a separate drawable interface instance, wherein each of the two or more sub-objects corresponds to a different drawable interface instance; (c) selecting one of the two or more sub-objects; (d) in response to the selecting, separately displaying the selected sub-object in the corresponding drawable interface instance (e) directly modifying, in-canvas, the selected sub-object using the corresponding drawable interface instance; (f) in response to the directly modifying, dynamically updating the terrain; and (g) displaying the updated terrain.