Spacedraw provides plenty useful and established tools for polygonal modeling and **retopology**

- they work with arbitrary complex topology: manifold and
**non-manifold meshes**, faces with any number of sides, edges shared by multiple faces - the operations can be applied to any number of elements at once, possibly from different objects
*normals*, vertex-colors and texture-coordinates are retained, resp. reasonable modified or generated- manually removing and combining elements
**deleting**faces

**removing**vertices or edges,**merging**the adjacent faces**collapsing**faces or edges**welding**adjoining vertices or edges to their center or a target- automatic
**stitching**and**simplifying meshes**, merging coincident vertices **bridging**between edges and faces- border- and non-border edges may be used
- edge-paths may be open or closed, the best connection is determined automatically, but the twist can also be adjusted manually

- multiple pairs of edge-paths or face-clusters can be welded / bridged at once, the nearest pairs are chosen automatically
**extruding**edges and faces- by moving, rotating and scaling, complex extrusions can easily be created
**subdividing**meshes- regularly, according to different patterns
**inserting edge loops**in face-paths, or around vertices or edges- manually
**“drawing” edges**on the surface **detaching**and**splitting**meshes- along edges and at vertices
**slicing**along a plane**chamfering**edges and vertices

Spacedraw introduces novel ways for deriving surfaces and solids from existing geometry:

- the
**inflate**-tool creates surfaces around lines and curves, or the edges of meshes - “
**pipes**” with any number of sides, or flat “stripes” may be generated, and their thickness can be adjusted overall and in places - at branchings, the simplest possible joints are created, yielding contiguous manifold surfaces from complex networks
- the tool may be used e.g. to create pipes, cables, frames, beams, trunks and branches of trees, blades of grass…

- the
**diverge**-tool gives thickness to existing surfaces by splitting them in two, either as a whole or in places - the displacement to each side can be adjusted and varied area by area
- at borders, flat or beveled rims can be created
- closed, contiguous surfaces are generated even from complex ramified constructs

*Spline surfaces *are curved surfaces that are defined by spline-networks, constituting their contours.

- they can be formed by
adjusting
**control points**and**handles**, providing excellent, intuitive control about their shape: - the surface passes exactly through the control points
- the surface spreads out parallel to the handles from the control points
- the handle’s length determine the curvature at the control points
- they are composed of two-, three- or four-sided
, bounded by splines*patches* - also, patches bounded by any combination of splines, straight lines and arcs can be created
- usual polygon faces and all kinds of patches of varying facet-count can arbitrarily be combined to contiguous surfaces
- any number of patches can meet at a vertex and at an edge, and they may converge there smoothly or angled
- four-sided patches can be assembled among themselves, and with three-sided patches and planar faces with good
**tangential- or curvature-continuity**(for practical purposes) - thus, spline surfaces are ideally suited to create complex organic objects
- the
adjoining handles can be rotated and scaled simultaneously to moving the control-points

- spline surfaces can be created by
- drawing the
**curve-networks**and then “covering” them with a surface **extruding**cross-sectional curves,- deriving them from existing polygon meshes, taking into account
the
*normals*to determine the curvature and locations of creases and cusps - they can arbitrarily be extended by extruding border- or interior edges to new patches
- spline surfaces or single patches can be converted to polygon meshes to make their facets editable individually, and parts of polygon meshes can be converted to spline surfaces