In brief
- Contour can create curves, points, or hatches where planes spaced in both directions from a start point intersect objects.
- Section produces planar output from the intersection of selected objects and a plane defined by two points.
- Both commands can output curves, points, or hatches; hatch creation depends on the object's section style and whether the section is closed.
- The Contour spacing and whether the Section plane is extended can be set through command options.
This guide shows you how to use Rhino 8’s Contour and Section commands to create evenly spaced contour curves from a 3D object or section curves on a specific plane. Both commands use geometry created by planes intersecting objects, but define the number and position of those planes differently. With Contour, you specify a start point, direction, and spacing; with Section, you use two points to define the section plane. This difference informs the workflow choice between generating a series of sections from an architectural model and creating a section at a single location.
What you’ll learn
You’ll learn how to place section planes at regular intervals in both directions from a start point with Contour, and how to create a section on a plane defined by two points with Section. You’ll also learn about the documented options for output type, assigning object properties, grouping the generated geometry, and creating hatches.
These commands can be used to obtain curves from the geometric intersections of an architectural or interior model. For example, generating a series of contours through a model serves a different need than creating a section at one location. The geometry produced depends on the selected objects and defined planes; the commands do not interpret or modify the design on their own.
Requirements
The commands documented in the source are for Rhino 8.
You need selected objects to use with the Contour and Section commands.
The command planes are perpendicular to the current CPlane. Before you begin, consider whether the active CPlane is suitable for the section direction.
The source documentation does not explain account requirements, licensing terms, hardware requirements, or the commands’ availability in versions other than Rhino 8. Do not make assumptions about these topics.
The source lists these commands under Curve From Objects. You can enter the command names in the Rhino command line or follow the menu and toolbar locations shown in the documentation. The steps here describe the basic operation of both commands; no additional interface settings are assumed.
Step by step: Create evenly spaced contours with Contour
Select the objects to contour. The command generates output where the spaced planes intersect the selected objects. The result depends on where the objects intersect those planes.
Run Contour and set a start point. This point determines the position of the first contour plane. According to the documentation, planes are generated in both directions from the start point, so think of it as the reference that determines the position of the contour series.
Define the direction perpendicular to the planes. The direction determines the path along which the contour planes are generated. Since the planes are created perpendicular to the current CPlane, the resulting contour direction is also related to the CPlane.
Enter the spacing between contours. This sets the distance between successive planes. Changing the spacing changes how frequently the intersection planes cross the object, but the source does not recommend an ideal value for any specific architectural use.
If needed, set the range or output type. The Range option sets the range over which contours are created. Under Output, All allows curve, point, or hatch output; with CurvesOnly, hatches are not created, and the output can be curves or points.
Review property and grouping preferences. Under AssignProperties, ByCurrentLayer creates output on the current layer with By Layer object properties. ByInputObject inherits properties from the input objects. GroupObjectsByContourPlane places objects created on the same contour plane into a group.
Step by step: Create a section on a single plane with Section
Select the objects to section and start the Section command. The command can create planar curve, point, or hatch output from the intersection of a plane with the input objects.
Choose two points to define the section plane. Section uses these two points to define the plane. The planes are perpendicular to the current CPlane, so the CPlane’s orientation should match the section direction you want.
Decide whether the plane needs to be extended. The ExtendSection option determines whether the section plane extends beyond the points you picked. When using this option, decide whether the plane should stop at the specified points or continue beyond them.
Choose the output format. Under Output, All allows curve, point, or hatch output. CurvesOnly disables hatches and produces curves or points. For object properties, you can use ByCurrentLayer or ByInputObject; objects created on the same section plane can be grouped with GroupObjectsBySectionPlane.
Common situations
The contour direction isn’t what you expected: Check that the planes are generated in both directions from the start point and that the selected direction is perpendicular to the planes. Also keep in mind that the planes are created perpendicular to the active CPlane.
The contours are too dense or too sparse: Review the distance between planes in the Contour command. The spacing determines how frequently contours are created across the object.
No hatch appears: Even when All is selected, hatches are created only for closed contours or sections and when the input object’s section style allows it. No hatch is created if the object’s section style is By Clipping Plane. If you don’t need hatches, use CurvesOnly.
Object properties aren’t as expected: Under AssignProperties, check whether you want to use the current layer’s properties or inherit properties from the input object.
You need a series of sections rather than just one: Section creates an intersection with a single plane; if you need multiple planes at regular intervals, consider using Contour.
Use in architectural and visualization workflows
For architects, interior designers, and visualization teams, the key difference between the two commands is how the sections are positioned: Contour creates a series of results using spaced planes, while Section creates a section on a plane defined by two points. So, try Contour if you want a series of intersection curves from a model, and Section if you need a section on a specific plane. The option to output curves, points, or—under the right conditions—hatches provides flexibility for different drawing needs.
However, the documentation does not provide information about compatibility with a particular render engine, file transfer, hardware performance, or licensing costs. In a real project, check that the results match the intended section direction in the model; in particular, review the CPlane, output type, and property assignment settings against your team’s standards. The source does not support any conclusion that using these commands requires a particular graphics card or computer specification.
Next steps
Start by defining a Section plane on the same model and reviewing the output. Then compare the results of a plane series created with Contour by changing the start point, direction, and spacing. If you expect hatches, check whether the sections are closed and review the object’s section style. Set grouping and property options to suit your needs. When evaluating how the commands behave, changing one variable at a time—for example, spacing or direction—makes it easier to see which setting affects the result.
Source and license
This tutorial was adapted into Turkish from McNeel’s Rhino 8 help documentation for the Contour and Section commands. The documentation is provided as a freely licensed resource. No sample prompts or code were taken from the source text; the steps have been presented in original wording.
Sources
2 sourcesSource texts are not republished; short quotes are marked, everything else is our own summary and commentary.
Contour and Section offer architects’ offices and students who need to create intersection geometry from a Rhino model two straightforward methods. The clear distinction between a series of contours and a section on a single plane makes it easier to decide which command to start with; output and grouping options also provide flexibility in organizing results.
For teams in Turkey, the key consideration is whether these commands fit their existing modeling workflow. Since the source provides no information about licensing costs, hardware requirements, or compatibility with other software, these points need to be verified separately before making a decision. In particular, don’t overlook the CPlane and the conditions for creating closed sections.
Frequently asked questions
What does the Contour command do in Rhino 8?
Contour intersects selected objects with evenly spaced planes to create curves, points, or—under the right conditions—hatches. The planes extend in both directions from the start point.
How do you create a section with the Rhino Section command?
Select the objects to section, then specify two points to define the section plane. The plane is perpendicular to the current CPlane.
Why might a section hatch not be created in Rhino?
Hatches are created only for closed contours or sections and when the object’s section style allows it. No hatch is created when the section style is By Clipping Plane.
