Your model already understands parameters. Now you need to learn something just as important: recognize physical regions even if the length, mesh and internal numbers change that MAPDL assigns to nodes and elements.
YOUR MISSION
You will build five named regions: the fixed end, the tip, the top face, the top edge of the tip and a central band of elements. You will then modify the beam and you'll see that they all still exist without typing a single ID.
Guiding Question How do you program a physical region when you don't know its node numbers yet?
Objectives
By completing M02 you will be able to demonstrate that:
- You distinguish entities from the solid model and the finite element model.
- Explain why a selection is a temporary state and a component is a persistent reference.
- You combine sets by
S,A,RandU. - You select nodes by location and elements by position of their centroid.
- You explicitly control tolerance by
SELTOL. - You use a local system as a mobile reference linked to the tip.
- Audits components with
*GET,COUNTand relationships between counts. - You retrieve the complete model before continuing through
ALLSEL,ALL.
Prerequisites and files
- Have completed M01 or understand parameters, expressions and checks with
*IF. - Recognize that the beam occupies
0 ≤ X ≤ beam_l,0 ≤ Y ≤ beam_hand0 ≤ Z ≤ beam_b. - Keep the system consistent SI: meters, newtons and pascals.
02_start.macStarting point.02_geometry_selections.mac— guided solution and audit.02_bug_hunt.mac— five deliberate defects.02_challenge.mac— challenge template.02_expected_results.csv— self-correction contract.
How to use this lesson
| Route | Duration | Stroke |
|---|---|---|
| First win | 30–35 min | Prediction, parametric geometry and first components audited. |
| Complete | 70–75 min | In addition, intersections, executable contract, bug hunting and challenge. |
Recommendation: Think of each region as a whole before writing NSEL. If you can't predict how many entities will capture a selection, you still don't understand it.
Session map
- Mission: objectives, downloads and prediction on regions.
- Mental models selection as state and set algebra.
- Demonstration: geometry, components and audit contract.
- Error hunting: empty and overlapping components.
- Challenge: modify a region with passes=1.
- Mastery: final test that records demonstrated mastery and recommends M03.