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Geometry creation

Botcha gives you several way of creating geometry. Each option that is given is though as a parametric object that can be created with simple 2D interactions. The idea is that by connecting 2D objects you will be able to generate 3D geometry.

Generator view

Lofts

The loft will create a 3D object by fitting surfaces across several profile curves that defines the shape. This will allow you to create easily complex figures by interpolating several curves. There are a number of options that you can set for each curve. When editing a loft you will be able to move the sections around and the software will automatically interpolate (using a bezier curve) between the curves.

Sweeps

Sweeps are generated by extruding one or more section along one or two rails. In this generator you will be able to create a number of sections and have then swept along a rail to generate a tube-like 3D object. There is the option to use two different rails, this will scale and rotate the section based on the position of the second rail with respect to the first.

Revolutions

Revolution are made by rotating a section around a given point, to keep it consistent and flexible as the other generators we added the possibility of using multiple sections

Using the geometry generators

From the default view you can click on one of the buttons to create a new geometry generator. Alongside it, also the generated mesh is added to the model. The user is then automatically taken to the generator edit view. Each generator has unique properties but a lot are shared.

Generators

One of the first thing you have to be mindful when generating geometry is about the direction of your sections, this will determine the direction the triangles will be generated for the mesh.

LoftUI

There are some general properties of the generator that can be edited form the contextual toolbar or using a panel that can be opened using the gear button (Z).

  • Relative (A): Each section has its own transformation in 3D space. If the generator is set to "Relative", a section transform depends on the one that comes before. This means that if you move Section 8, for example, you will move also sections 9 and 10. This property can only be modified in loft generators.

  • Samples (B): To translate the section into 3D geometry we must pick a certain amouts of points from the curve to generate mesh vertices. This property regulates how many points should be sampled. The higher the number is, the better the geometry will fit the curve. Keep in mind that too many vertices are complex to handle, try to minimize this value.

  • Steps (C): This parameter determines how many vertices should be sampled between each pair of sections. This value at 0 means a straight connection between sections, while a higher value means a smoother curve. As for the samples, try not to raise this parameter more than necessary.

  • Front and Back patches (D): It is possible to close the first and the last section of the generator with a planar patch.

  • Opacity (E): Sets the opacity to the section drawing panel.

The toolbar contains a set of commands that are the same for all generators. Some are similar to other commands in canvas.

  • Draw with control points (F): Begin or continue to draw curve for selected section setting control points.

  • Draw Interpolated (G): Begin or continue to draw curve for selected section interpolating points.

  • Draw shape (H): Draw curve for selected section as an ellipse, rectangle, rounded rectangle or polygon.

  • Edit curve (I): Edit curve of the selected section.

  • Transform curve (L): Transform the curve of the selected section in 2D.

  • Change section direction (M): Each section has a start point and a direction used to generate the mesh. Two sections are connected beginning with their start ponit and following their directions. This command invert current direction for the curve.

  • Change section start (N): Each section has a start point and a direction used to generate the mesh. Two sections are connected beginning with their start ponit and following their directions. This command let's you pick a new point to be used as starting point for selected section.

  • Show neighbour sections (O): Show in the drawing area the previous and the following section curve (see image). The previous curve is displayed in light gray, the folowing in dark gray. The starting point and the direction of the neighbors is also displayed.

  • Match panel and 3D view (P): Sets zoom level of the panel to match 3D view distance (left click) or vice versa (right click). It is recommended to use this command in ortho mode camera.

The right panel shows the list of sections and a few commands. The sections are in inverse order (the bottom most is the first section). As for most items in Botcha, sections names can be changed double clicking their name label.

  • Transform section in 3D (Q): Transform the section in 3D using the gizmo. This is a loft specific feature.

  • Trash bin: delete the section.

  • Stop interpolation (R): The sections are interpolated to obtain a smooth curve between them. If you need to stop the curve flow you can activate this property for the section. (example in the image above)

  • Distance (S): This property is different between generators:

    • In loft: the distance in mm from the previous section.
    • In sweep: the position of the section on the rail expressed in percentage.
    • In revolve: the angle of the rotation in degrees.
  • Add new section (T): Adds a new empty section just after selected one.

  • Duplicate selected section (U): Adds a specified amout of sections copyed from selected one.

  • Change sections direction (V): Change the direction of all the sections. (see toolbar command M)

  • Propagate section (W): Sets the same curve of the selected section to all the following ones.

  • Generator properties (Z): Opens a panel to edit generator properties.

Warning

The generators are supposed to generate a geometry from scratch, and they must contain all informations to do that. Infact, a small change in one section refreshes the entire mesh. There are some operations that modify mesh geometry: Components separation, Mesh cut, Weld and Bake Mesh. Performing one of this operations will detach mesh from it's generator, because the operation result would be otherwise overwritten by the generator refresh. Entering the generator context with a detached mesh will open up a panel that asks if you wish to create a new generated mesh.