Video 1: Intro to Karamba3D (Beam Structure with Two Connections)

This is the first video in the Karamba3D series. It stays intentionally simple: a single beam, fixed at both ends, loaded at two interior points. The goal is to walk through the full workflow once (geometry, beam creation, supports, loads, analysis, and results) so every later video builds on this foundation.

Karamba3D is accessed through Grasshopper, which is built into Rhino.

What you'll build

A beam with a support at each end (both ends fixed, not pin/roller) and two downward point loads applied at interior points along the beam. By the end, you'll see the beam visibly deform under load and view a color map showing where it's most stressed.

1. Rhino setup

• Open Rhino. Set your units before doing anything else: type units, and set the model units (e.g. feet) in the dialog. Confirm the unit shows correctly in the bottom left corner of the viewport.
• Type grasshopper to open the Grasshopper canvas. If you see a compatibility warning mentioning Karamba, ignore it, it doesn't apply here.
• In Grasshopper, switch to the 3D display.
• Turn on grid snap in Rhino before placing points. This keeps everything aligned and makes the geometry easier to follow.

2. Geometry: points and lines

1. Type point in Rhino and place 4 points left to right:
   • Point 1: left support
   • Point 2: first load point
   • Point 3: second load point
   • Point 4: right support
2. Use spacebar to repeat the point command for each additional point.
3. Type line and connect them in order: support to load 1, load 1 to load 2, load 2 to support. This creates 3 separate line segments covering the full span.
4. Press F7 to hide the grid and clean up the viewport.

3. Bringing geometry into Grasshopper

• Place a Curve parameter (double-click the canvas, type crv). Right-click it, choose Set Multiple Curves, select all 3 line segments in Rhino, then press Enter.
• Karamba can't read curves directly as structural elements. Feeding a Curve straight into a Karamba component will throw a "data conversion failed from curve to element" error.
• Add Create Linear Element (Karamba3D → Model), also labeled LineToBeam. Wire the Curve output into its Line input. This converts the 3 curves into one continuous beam. Karamba reads shared endpoints and welds the segments into a single element.

Tip: You can add any Grasshopper/Karamba component by double-clicking an empty spot on the canvas and typing its name, instead of hunting through the tab menus.

4. Assemble Model

• Add Assemble Model (Karamba3D). This is the component that will collect the beam, supports, and loads into one structural model.
• Wire the Elem output from Create Linear Element into the Elem input of Assemble Model.

5. Supports

• Add a Point parameter, right-click it, choose Set Multiple Points, then select the two outer points (the supports) in Rhino and press Enter.
• Add a Support component (Karamba3D → Support). Wire the Point output into its position input.
• On the Support component, check all six degrees of freedom: Tx, Ty, Tz, Rx, Ry, Rz. This fixes both translation and rotation at each support, so both ends are fixed, not pin/roller. Leaving any of these unchecked would let that support move or rotate freely in that direction, which isn't what we want here.
• Wire the Support output into the Support input of Assemble Model.

6. Loads

The Load component needs a force vector (direction and magnitude), not just a point.

1. Add a Unit Z component (double-click, type unit z). This gives a vector pointing straight up along Z by default.
2. Add a Multiplication component. Wire Unit Z into input A.
3. Add a Number Slider (double-click, type a number to auto-create one, e.g. 50). Wire it into input B. Dragging this slider scales the load's magnitude.
4. Direction check: Unit Z points up by default, which will deform the beam the wrong way. Add a Negative component and route the slider's value through it (into the X input), then into the Multiplication input, so the force vector points down in the direction of gravity. Confirm the deformation direction flips correctly once this is wired in.
5. For finer control over load magnitude, delete the default number slider and replace it with one set to a smaller range. Double-click and type 0.01 < 10 to get a slider from 0.01 to 10 with fine steps.
6. Add a Loads component. By default it's set to Gravity, which applies uniformly across the whole beam by mass, not what we want, since the loads need to be local to the two middle points.
7. Click the Type of Load dropdown on the Loads component and switch it to Point Load. This adds a new position input.
8. Wire the Multiplication output into the Force input.
9. Add another Point parameter, right-click it, choose Set Multiple Points, then select the two middle points (the load points) and press Enter. Wire this into the new position input on Loads.
10. Wire the Load output into the Load input of Assemble Model.

7. Analyze and visualize

1. Take the Model output from Assemble Model and feed it into an Analyze component (double-click, type analyze, pick the first result).
2. Add a ModelView component (double-click, type model view). Wire the Model output into it. This shows the beam's deformed shape directly in the Rhino viewport.
3. If the deformation looks extreme, it's almost certainly the load multiplier value. Drag the number slider down to reduce it and watch the deformation scale down accordingly.
4. Click Display on the ModelView component to adjust how exaggerated the deformation appears, and to toggle the degrees of freedom icons at the supports on/off.
5. Add a BeamView component (double-click, type beam view). Wire the Model output into it. This wraps a pipe-like render around the beam.
6. Click Display on BeamView and select Axial Stress. Sections under the most stress render red; sections near the supports with less stress trend toward purple/blue.

Navigation tip: middle-mouse-click over a component to bring up a quick menu, then hit Zoom to snap your viewport to that part of the model. Helpful when the canvas gets crowded.

Recap: what each component does

Component	Role
Curve	Brings the 3 Rhino line segments into Grasshopper
Create Linear Element (LineToBeam)	Converts the curves into one continuous beam element
Support	Marks the two outer points as fixed supports (all 6 DOF locked)
Unit Z, Negative, Multiplication	Builds a downward force vector with adjustable magnitude
Loads (Point Load)	Applies that force vector at the two middle points
Assemble Model	Combines the beam, supports, and loads into one structural model
Analyze	Solves the model for displacements and internal forces
ModelView	Shows the deformed shape
BeamView	Colors the beam by stress (axial stress, in this video)

Support and Load components serve the same basic role as Create Linear Element: they translate Rhino geometry (points) into data Karamba can use for analysis. Assemble Model is where everything, geometry, constraints, and loads, comes together into the final model that gets analyzed.