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 executing in a computer, 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, in the computer, 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, in the computer, one of the two or more sub-objects; (d) in response to the selecting, separately displaying, on a display device communicatively coupled to the computer, the selected sub-object in the corresponding drawable interface instance (e) directly modifying, in-canvas via the computer, the selected sub-object using the corresponding drawable interface instance; (f) in response to the directly modifying, dynamically updating the terrain; (g) displaying, on the display device, the updated terrain; (h) selecting one of the two or more sub-objects corresponding to an existing ground and clicking repeatedly; and (i) in response to the selecting and clicking repeatedly, showing sequential stages with which the existing ground was modified incrementally with each operation applied to the existing ground to reform the existing ground into the updated terrain.