Open topic with navigation

Parametric Objects

Parametric objects provide basic shapes, such as a sphere, cube, or cylinder. As a result, they often provide the basis for modeling more complex shapes, but they can also be combined to directly represent simple objects. The advantage of these objects is that their shapes can be retrieved directly and configured using numerical values and options. After conversion to an Editable Object, these shapes can then also be used as a basis for the use of Modeling Tools or combined with Sculpting Tools as a Sculptable Mesh.
Special parametric objects, such as the Sweep Object and the Lathe Object directly allow the creation of organic shapes based on manually drawn curves. This allows you to directly model tubular or hose-shaped objects, as well as rotationally symmetrical objects.

Table of content

• Creating parametric primitive objects
• Editing parametric primitive objects
• The Sweep Object
• Editing the drawn spline
• Editing the contour of the Sweep
• The Sweep Object Settings
• The Lathe Object
• The Lathe Object Settings
• Null Object

Creating parametric primitive objects

The first opportunity to create a parametric shape comes directly when creating a new project. You will find all available basic shapes as icons on the Start Menu page (see figure below).

Starting with a new project gives direct access to parametric objects directly from the Start Menu.

After selecting one of the shapes or just using the New command in the top right, Forger switches to the working layout. To add additional parametric objects to the project, just open the Objects List and click on its Plus (+) icon. This brings up a list of all available parametric objects. In addition, cameras and light sources can also be found in this menu, which can also be added to your scene in this way.

Editing parametric primitive objects

	After adding the needed shape, you can proceed directly with the configuration of the selected object. To do this, open the Objects menu and select the entry of the object you want to customize. The arrow to the right of the object entry names will take you to the specific settings window. Alternatively, you can directly find the icon of the currently selected object in the upper main menu bar. A click on it also opens the settings window of this object, without you having to switch to the Objects list first.
	The Transform settings are not specific to parametric object. They are available for all object types and allow the exact placement and scaling of objects, including cameras and lights. When working in Model mode, all primitive objects also offer an option to be converted to an Editable Mesh, allowing the object to be accessed by the modeling tools and use the Point, Edge and Polygon modes. You can access the conversion command directly via the icon found in the upper right corner of the object settings (see red marking in the figure on the left). Just note that converted primitive objects loose all of their parameters and have to be edited on the level of points, edges and polygons.
	In the Basic tab you will find the basic settings of the object, which are mainly used to define its size and proportions. These settings are specific to the selected object. Rotationally symmetrical objects, such as a sphere, cone or cylinder offer radius values, angular shapes, such as a cube or plane are defined by dimensions along their axes. Segment settings generally determine the number of polygons on the object and can influence the quality of the shape display, especially for rotationally symmetrical objects.
	The Caps settings are available only on the objects that have disk-shaped areas that can be used to close the top and bottom of the basic shape. For example, think of a cylinder that can be closed at the top and bottom. Without this area, the cylinder becomes an open tube.
	Some rotationally symmetrical objects, such as a Cylinder or a Cone, can also be created only in a section or a slice. For this purpose, an angle range to be displayed can be activated in this Slice tab.
	The Other tab is again not specific to parametric primitive objects, as materials can be assigned here or the shading angle of the surface can be defined. For more information on creating, applying and editing materials, click here.

The Sweep Object

This object is always useful when modeling cables, hoses, pipes or similar shapes. The basis for this is a spline curve through which the center line of the hose shape runs. This curve can be drawn as a freehand line or created point by point in its course. For this purpose, the Sweep Object provides its own spline drawing tool, which is also used by the Lathe Object. You will therefore find many parallels in the creation of a Sweep Object and a Lathe Object.

Activating the Sweep Tool in the Toolbar displays new icons in the left menu bar, which are described below.

Opens the settings for the Sweep Tool. Some of these settings are also available as icons (described below) or can be controlled directly in the viewport. Here you can switch between the Drawing mode, to create or edit the spline curve, or the Camera mode, to be able to change the perspective in the viewport without triggering the creation of new spline points. Here you can choose between the Freehand Pen Mode or the Drag Tangent Pen Mode to create a spline curve. The later allows the creation of individual spline points and tangents by dragging in the viewport (if you're creating a Bezier spline). In Freehand mode you can draw the complete spline with one stroke and the points and tangents along the curve are created automatically. In both cases all points and tangents can be edited later as well. The Magnet icon activates the Depth Snapping so that the drawn spline can be drawn directly to an existing surface in the viewport. Activating this icon allows to add a new segment to the end of an already existing curve. If this option is off, starting a new drawing will create a new, separate spline, also resulting in the creation of new Object in the Objects list.

Besides the options available as icons, you can also open the settings of the Sweep Tool to configure, for example, the type of spline drawn and its interpolation. These settings must be made before drawing the curve.

Pen Mode: Offering Freehand mode and Drag Tangent mode for the creation of the spline curve. Curve Type: Controls the interpolation of the curve between the curve points: Linear: The drawn points are connected with straigth lines. No rounding is applied and no tangents can be used to control the curvature of the spline curve. Bezier: This is the only Curve Type to support tangents at the drawn points, giving the most precise control over the curvature und interpolation of the spline curve. B-Spline: This results in a very rounded, organic spline curve without the option the use tangents. The curve might not run through the given points exactly. Depth Snapping: This has to be active if you like to draw a spline curve onto the surface of another object in the viewport.

• Fitting Tolerance: Used only in Freehand Pen Mode. At higher values, the resulting curve may deviate more from the originally drawn shape. Practically, this means that fewer points are created along the curve and only stronger changes of direction are included in the resulting curve.
• Smoothing: Used only in Freehand Pen Mode. This sets the amount of smoothing that gets applied to the created spline curve.
• Contour Size: This is the radius used along the drawn spline curve to create the surface of the sweep object. This value can be adjusted at any time, even after the spline curve has been drawn. This radius can also be edited by dragging the handle at the red endpoint of the drawn spline.
• Copy Contour Of Selection: By default a circle is used as a contour for the Sweep, but you can also edit the circle shape to your liking. In that case, having this option active, the next drawn Sweep will use the same contour by default. Here you can find more information about editing the contour of the Sweep.
• Embed: This value is used only in combination with an active Depth Snapping and sets the distance between the spline curve and the surface on which it is drawn. This value must be set before starting to draw. Positive values lower the resulting spline curve, negative values raise the drawn spline above the surface it is drawn on. Since the selected value is multiplied by the Contour Size, a subsequent change of the contour size does not update the distance between the surface and the drawn spline.

Editing the drawn spline

After a spline curve is drawn, you can still add additional points and control the shape of the curve by moving the existing points. If the Bezier Curve Type has been used, all tangents can also still be rotated and scaled to control the curvature of the spline. Tangents can even be switched between hard and soft interpolation, and both tangents of a spline point can be broken. The following pictures show some examples of this and how it is done.

Example of a drawn Bezier curve used to create a Sweep Object.

As you can see in the image above, the curve always starts with a green point (1) and ends with a red point (3). If you decide to add an additional spline segment afterwards, it will always be attached to the red endpoint of the curve. Attached to the end there is also always an additional handle point attached to the side (4). Moving this point will scale the Contour Size, defining the radius of the circle used to create the tubular Sweep Object. The other points along the curve (2) define the curvature and shape of the spline. All points can be moved to shape the curve to your liking. You can also select multiple points at once using the + and - selection modifier keys.

When you tap on a point, an additional set of icons will appear and you will have access to the tangents of that point if a Bezier curve was used.

Switching between soft (left) and hard tangent interpolation (right)

With a double tap on a point along the curve, you can switch between the soft interpolation of the tangents and the hard interpolation of that point. This way you can mix organic and curvy spline parts with linear interpolated segments as shown in the image above. Having a point selected will also give access to three new icons that are displayed below the point by default. We walk though them from left to right:

• Placement: This option is relevant only for the placement of the icons. In the state with the three horizontal bars, the three icons are always displayed directly under a selected point. Just drag this icon to reposition the icons to your liking. The symbol will then change to a curved arrow. The icons will then be fixed to this new position, even if another point is selected. A tap on the curved arrow icon will reposition the icons under the active spline point selection.
• Trash can: A tap on this icon will delete the selected point from the spline. New points can always be added with a tap on a spline segment between two existing points.
• Split: This command is available only for points that have at least one more point in the direction of the end points of the curve as a neighbor. The selected point is removed and a gap is created in the curve.

Switching the orientation of the Bezier tangents

The endpoints of the tangents can be moved directly to edit the length and direction of the tangents. In addition, a double tap on these endpoints can be performed to toggle constraints for the tangent directions and lengths. The current state is indicated by the shape of the spline point. A square point allows individual configuration of both tangents at this point (see left side of figure above). This allows them to point in different directions and have different lengths. With a circular spline point, both tangents remain on one continuous line (right side in the figure above).

Editing the contour of the Sweep

By default, the Sweep Object is used with a perfect circle as a contour, resulting in a tube like object, but this circle curve can also be edited by manually moving its four points. You already have seen, that the radius of this Contour circle can be edited directly by moving the side handle at the red endpoint of the sweep curve or by using another Contour Size value in the Sweep Tool settings. To change the shape of the circle contour, tap once on the contour at the green starting point of your curve. this will give access to the fours points that define the circle contour. You can then select and move these countour points to your liking, work with their tangents or even add and delete points at the contour. The following image captures these steps.

Editing the shape of the contour spline

The above image highlights the contour spline at the starting point of the Sweep curve on the left in green color. Just tap this contour to get access to the points along that contour and edit this curve to your liking (see right image above). You can even tap on the curve to add more points to it or use the trash can icon below to delete selected points that are not needed. If you like to use the modified contour also for the next created Sweep Objects, take care to activate the Copy Contour Of Selection option in the Sweep Tool settings before drawing the next Sweep Object.

The Sweep Object Settings

The shape and style of the created Sweep Object can be further edited by opening the Sweep Object settings.

The Base Settings End Scale: The contour spline will always be used in its original scale at the beginning of the Sweep curve. By lowering this value the contour gets smaller toward the end of the Sweep curve. End Rotation: The Contour can get rotated by this value along the Sweep curve. Start Growth/End Growth: By default the entire length of the Sweep curve is used with the contour spline to calculate the Sweep Object. Increasing the Start Growth value shortens the Sweep Object from the beginning. Decreasing the End Growth is shortening the Sweep Object at its end. Parallel Movement: If this option is enabled, the contour is swept in a parallel manner (i.e. it is not rotated at all). Constant Cross Section: This option is enabled by default and causes the contour spline to be scaled at hard edges in order to maintain a constant thickness throughout the sweep.

• Banking: If enabled, the contour spline will lean into the curves of the sweep curve. The initial banking angle is set to the average plane of the path spline, which is calculated from the position of the path's spline points. The banking angle must be chosen at random for straight lines since they cannot define a plane. In this case, turn off Banking to make the contour run parallel to the sweep spline's XZ plane.
• Keep Segments: The effect of this option is only noticeable while changing the Growth values. If the option is disabled, you have a smooth change in Sweep generation. With Keep Segments, the sweep grows or shrinks segment by segment.
• Flip Normals: Flips (i.e. reverses the direction of) the Normals of the Sweep Object. Usually, Forger will point the Normals in the correct direction. However, with open contours it is not possible for Forger to know which way they should point. In this case, you can reverse the direction of the Normals with this option, if needed. This option does not effect the caps, since their Normals are always calculated correctly.
• Stick UVs: A Sweep Object's U-coordinates normally range from 0 to 1 over the entire length of the spline. If the length of the Sweep Object is reduced using either Start Growth or End Growth, the Stick UVs setting defines if U should continue to run along the entire length of the spline or if it should adapt to the length of the spline. The latter option will scale an applied texture when the Growth settings are modified.

The Caps Settings Start Cap: If the Contour spline is closed (see Contour Closed option in the Curve tab) , use this option to add a cap at the start (green point) of the Sweep curve. End Cap: If the Contour spline is closed (see Contour Closed option in the Curve tab), use this option to add a cap at the end (red point) of the Sweep curve. Cap Type: Here you can choose the polygon type and structure used to close the caps: Regurlar Grid: A regular grid of equally sized polygons is used for the caps. This grid is only broken up in the edge area of the caps. N-gons: A single N-gon is used as a cap. Delaunay: This creates an adaptive structure of triangular polygons in the cap areas. The triangles get smaller near the borders of the caps. Triangles: Only triangluar polygons are used for the caps. Quadrangles: The algorithm tries to use only quadrangular polygons for the caps, but triangles may still appear.

The Curve Settings Path Curve Type: This allows you to switch the interpolation type of the Sweep path curve. Only the Bezier type is able to use Tangents. Path Closed: Activate this open if you like to create a spline connection between the first and the last point of the Sweep Spline. Contour Curve Type: The Contour spline can use its own interpolation type. Note that only the Bezier type is able to offer Tangents. Contour Closed: This option is active by default to be able to use Caps at the open ends of the Sweep Object. Contour Scale: This is a multiplicator value for the size of the Contour spline.

The Lathe Object

The Lathe Object is always suitable for modeling when rotationally symmetrical objects are to be created, such as a bottle, a vase or a glass. These shapes can be modeled by drawing a half cross-section of, for example, a vase as a spline curve (Contour Spline). By rotating this curve around a perpendicular axis, the complete object is then created. An additional option allows the contour curve to be moved along the vertical while rotation takes place at the same time. In this way, snail shells or, for example, corkscrew shapes can also be created.

After activating the Lathe Tool, the creation takes place in two steps:

1. Tap once in the viewport or drag a held tap around in the viewport to place the origin system for creating the Lathe shape. The representation of this system consists of a vertical line by which the axis of rotation is indicated. When subsequently drawing the Contour spline, it should always be on one side of this axis only.

2. After placing the virtual potter's wheel of the Lathe Tool, the tool automatically switches to the drawing mode and you can directly start creating the Contour. The Lathe tool provides the following options for this purpose:

The two steps of the Lathe Object creation: On the left, the origin system of the Lathe has been placed and on the right you can see different perspectives of drawn Contour curves and how they get rotated and duplicated around the rotation axis to shape the object.

Pen Mode: Offering Freehand mode and Drag Tangent mode for the creation of the spline curve. Curve Type: Controls the interpolation of the curve between the curve points: Linear: The drawn points are connected with straigth lines. No rounding is applied and no tangents can be used to control the curvature of the spline curve. Bezier: This is the only Curve Type to support tangents at the drawn points, giving the most precise control over the curvature und interpolation of the spline curve. B-Spline: This results in a very rounded, organic spline curve without the option the use tangents. The curve might not run through the given points exactly. Depth Snapping: This has to be active if you like to draw a spline curve onto the surface of another object in the viewport. In the context of the Lathe Object, this should be switched off, as the contour gets rotated around the vertical axis of the Lathe system for geometry creation.

• Fitting Tolerance: Used only in Freehand Pen Mode. At higher values, the resulting curve may deviate more from the originally drawn shape. Practically, this means that fewer points are created along the curve and only stronger changes of direction are included in the resulting curve.
• Smoothing: Used only in Freehand Pen Mode. This sets the amount of smoothing that gets applied to the created spline curve.

While drawing the contour spline the Lathe Tool offers the same options as icons in the left Toolbar as the Sweep Tool. Just can find all info about these icons here.
Also editing the Lathe Contour splines works just the same as editing the Sweep spline. You can read about these options here.

The Lathe Object Settings

The shape and style of the created Lathe Object can be further edited by opening its settings.

The Base Settings Angle: For a closed Lathe Object, the drawn Contour Spline must be rotated completely, i.e. 360°, around the vertical. Smaller values therefore only lead to a partial representation of the Lathe shape. But values above 360° can also be used meaningfully if an increased Movement value is used at the same time. Subdivision: Sets the number of steps to convert the selected Angle value to polygons in the direction of rotation. The higher this value, the more rounded the Lathe shape will appear. Movement: During the rotation of the Contour, it can be simultaneously displaced along the vertical. This leads to helix-like structures. The Movement value indicates the magnitude of the vertical contour displacement. Scaling: This also allows the Contour to be scaled during rotation around the vertical. Values below 1 lead to a reduction of the Contour size, values above 1 increase the Contour step by step on its way around the rotation axis.

Flip Normals: Flips (i.e. reverses the direction of) the Normals of the Lathe Object. Usually, Forger will point the Normals in the correct direction. However, with open contours it is not possible for Forger to know which way they should point. In this case, you can reverse the direction of the Normals with this option, if needed. This option does not effect the caps, since their Normals are always calculated correctly.

Example of the same Contour spline used, but with a low Subdivision (left side) and a higher Subdivision (right side).

Example of on increased Movement value in combination with a reduced Scaling value. On the right side the Angle value has been increased over 360° to add even more twists to the shape.

The Caps Settings Start Cap: If the Contour spline is closed (see Curve Closed option in the Curve tab), use this option to add a cap at the start of the Lathe curve. End Cap: If the Contour spline is closed (see Curve Closed option in the Curve tab), use this option to add a cap at the end of the Lathe curve. Cap Type: Here you can choose the polygon type and structure used to close the caps: Regurlar Grid: A regular grid of equally sized polygons is used for the caps. This grid is only broken up in the edge area of the caps. N-gons: A single N-gon is used as a cap. Delaunay: This creates an adaptive structure of triangular polygons in the cap areas. The triangles get smaller near the borders of the caps. Triangles: Only triangluar polygons are used for the caps. Quadrangles: The algorithm tries to use only quadrangular polygons for the caps, but triangles may still appear.

Caps can only be created, if a closed Contour spline was used. The following image gives an example, using a reduced Angle value for the Lathe Object to make the Start and End Caps visible.

Contours can be closed with Caps

The Curve Settings Curve Type: This allows you to switch the interpolation type of the Contour curve. Only the Bezier type is able to use Tangents. Curve Closed: Activate this open if you like to create a spline connection between the first and the last point of the drawn Contour spline. Note that the Cap options can only be used with closed curves.

Null Object

This object is highlighted separately here because, although it can also be counted among the parametric objects, it does not itself provide any points, edges or polygons. Rather, it consists only of an axis system that can be highlighted by various shapes. The Null Object therefore does not react to light and cannot be covered with materials.

Nevertheless, a Null Object can be very useful if, for example, various objects are to be grouped together. In this case, simply create a Null Object and place it at the coordinate in the scene that is to serve as the position or pivot point for rotations. Then arrange the objects to be grouped as child objects under the Null Object. Any change in Translation, Rotation, Scaling and even its Visibility state is then transfered to all child objects as well. For more information, about how to create such groups, have a look at the Objects List.

Null Objects can also be used to control the position of the focal plane if they get linked to the cameras Depth of Field settings or the global Depth of Field Display settings.

These are the specific settings of a Null Object:

Shape: Here you can find several preset shapes that can be displayed at the position of the Null Object. Radius: This sets the overall size of the chosen Shape. Aspect Ratio: This controls the X to Y ratio of the chosen Shape. Orientation: Here you can choose between the Camera object's viewing direction or the default direction along the X, Y and Z axes to align the selected Shape.

Here you can see the representation of a Null Object for which a Diamond Shape has been selected. This shape was enlarged using the Radius value and automatically aligned with the Camera using the Orientation setting. When the Null Object is selected, its axis system becomes visible at the same time (see upper part of the illustration). Otherwise, in the deselected state, only its position as a point and the selected Shape are visible.