Build the stratigraphic proxies in Blender ========================================== .. _howto_build_proxies: .. note:: This how-to is adapted from *Exercise 3 — 3D modelling the stratigraphy* in the Reconstructive Archaeology handbook. Once the stratigraphic reading of an object, an architecture or an excavation has been formalised through an Extended Matrix (`see how to draw one `_), it is time to represent that stratigraphy in 3D space. Each US in the matrix gets its own **proxy** — a lightweight 3D placeholder that materialises the unit and is bound to the corresponding node in the graph. Prerequisites ------------- * EM Tools installed in Blender — see :doc:`../installation`. * A ``.graphml`` file produced in yEd — `see how to draw the matrix `_. * The reference data for modelling: a photogrammetric survey, an orthophoto, building plans and sections, drawings, written sources, or any combination of these. Step 1: load the references and the graph ----------------------------------------- If you have already prepared a ``.blend`` file in the ``SB`` subfolder (source-based modelling space), open it. Otherwise, start a new Blender file, delete the default cube, light and camera (``A`` ▸ ``X`` ▸ Enter) and import the references you will model from. Inside the EM Tools add-on (3D viewport ▸ N-panel ▸ *EM* tab) open the **EM Data Tree** section, select the ``.graphml`` file, and load it. For the full reference on this panel — supported file formats, GraphML ID conventions, statistics, colour schemes and visualisation options — see :doc:`../panels/em_setup`. Once the graph is loaded, create a collection named ``Proxy`` in the Outliner and make it the active collection — every proxy you create from now on will land there. Step 2: open the Stratigraphy Manager ------------------------------------- The **Stratigraphy Manager** lists every stratigraphic unit present in the matrix. Decide which US to model first, then begin with the standard procedure for adding a mesh object (``SHIFT + A``). For the full reference on filters, list rows, adding/editing US and the proxy-association controls used below, see :doc:`../panels/stratigraphy_manager`. Step 3: model the proxy ----------------------- Creating a proxy requires only minimal polygonal-modelling skill. The process is summarised below. 1. Place the 3D cursor in the viewport with **SHIFT + LMB** (left mouse button click), ideally at one corner of the structure whose proxy you are about to create. 2. Add a base geometry with **SHIFT + A**. In the vast majority of cases a cube is the right choice. 3. Raise the cube one unit on the Z axis (**TAB, A, G, Z, 1, Enter, TAB**), then scale it down to a manageable size (**S, 0.02, Enter**) — a freshly added cube is 2×2×2 m. 4. In *Edit Faces* mode, select a face and extend it in the desired direction (**TAB, 2, select face, G, G, hold ALT and extend, Enter or LMB, TAB**). 5. Repeat the extension on the other directions required (typically the X axis next). .. figure:: /_static/howto/build_proxies/proxy_modeling_process.png :alt: Sequence of steps for modelling a proxy in Blender. :width: 100% :align: center The proxy modelling process — five steps from base cube to fitted proxy. Step 4: associate the proxy with its US --------------------------------------- Once the proxy geometry is finished, select the corresponding US in the :doc:`Stratigraphy Manager <../panels/stratigraphy_manager>` and use the *associate* control to bind proxy and US. After binding, the proxy colour will reflect the colour scheme currently active in the EM Tools settings, and a closed-chain symbol will appear at the beginning of the corresponding row in the Stratigraphy Manager — a visual confirmation that proxy and US are successfully bound. Colour schemes (EM vs. Periods, custom property-based mappings, saving and loading ``.emc`` files) are documented in :doc:`../panels/visual_manager`. Step 5: model the rest of the stratigraphy ------------------------------------------ Continue modelling every other US already prepared in the EM. The result is a single Blender scene in which every proxy is bound to a stratigraphic unit in the graph, classified by epoch, and ready to be combined with the higher-detail representation models in the next stage of the workflow. For per-epoch selection, locking, visibility and *soloing* of the proxies you have just produced, see the :doc:`../panels/epochs_manager` reference. See also -------- * `Draw the Extended Matrix `_ — drawing the ``.graphml`` that feeds this exercise. * :doc:`20-em-2d-3d-linking` — the video-tied walkthrough of the same binding step. * :doc:`../panels/em_setup` — full reference for the EM Data Tree panel used in step 1. * :doc:`../panels/stratigraphy_manager` — full reference for the manager panel used in steps 2 and 4. * :doc:`../panels/epochs_manager` — full reference for the Epochs Manager panel. * :doc:`../panels/visual_manager` — colour schemes and visual settings applied to proxies.