3D reconstruction III. Preparing the workspace and blocking out the coffin lid

I’m modelling the reconstruction in Cinema 4D R20 Education. In the first step I’ve imported the SfM-model into Cinema 4D and added the previously chosen reference image to the top-view.

Modelling decisions for the lid

Following the contour of a coffin from Sedment (Taylor 2009, 407, tab VI) because the overall style and shape of the larger one (esp. hands, small face – large wig, painting on hand, no further decoration seen below hands, slight rounded sides) fits our lid fragment pretty well.

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Taylor 2009, 407, tab. VI: Cartonnage case with lids of outer and intermediary coffins from Sedment, 22nd-25th Dynasty, c. 945-700 BC. Intermediary coffin and cartonnage now Greenock, McLean Museum and Art Gallery 1987.394-5. (Photo courtesy Egypt Exploration Society).

Modelling decisions for the case

Using roughly the case from Taylor 2009, 406, tab V as reference because of the position of the tenons on our lid and the mortises on this case on the height of the hands. I’m using six tenons but four would also be possible (as we don’t have images from below our lid fragment to proof if there are two more mortises cut into the frame on the height of the face, no decision based on the fragment can been done). Most important is that aren’t eight connections used like, because they are a distinctive feature on Theban-style cases (see previous blog entry).

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Taylor 2009, 406, tab. V: Coffin and cartonnage case from Sedment, 22nd-25th Dynasty, c. 945-700 BC. Current location unknown. (Photo courtesy Egypt Exploration Society).

Modelling techniques for the lid outlines

  1. Drawing the outlines of a coffin lid half with linear splines along the reference image below the hands, above along the 3D scanned lid fragment (NB: fitting also to the 3D scan to get the right outlines of the coffin case).
  2. Extruding along y-axis with nearly the thickness of the wood boards (side edges will be bevelled at a later point), comparing the fit of the modelled coffin lid with the head fragment and making slight adjustments where necessary.
  3. Making backups.
  4. Rounding of the edges of the linear spline with selecting all points (without the two on the vertical half and lowest points for preserving straight edges there) and using the Round-tool.
  5. These steps back and forth until satisfied.

Modelling techniques for the first lid detailing and fitting to the 3D scan

Overall achievements needed for this step: Bringing the modelled board to the right thickness, bevelling of the outside edges, adding curvature to left board – following the shape of the SfM-model – flat foot section, as stated previously.

  1. Duplicating the extruded left side of the lid and mirroring it along the vertical edge to build the right side of the lid.
  2. Adjusting the width while preserving the shape, fitting it to the 3D scan and reference image.
  3. Since the right wood board is mostly flat and not curved convex like the left outer one: bringing the right plank to the same depth of the SfM-model and according to it the left half onto the same (curvature will be added separately).
  4. Merging both halves together, setting the edges where the halves were joined to the object-relative middle-point with switching to object(Rel)-positions. With this step these edges are also on the vertical middle axis of the 3D scanned lid fragment.
  5. Backups.
  6. Duplicating the non-bevelled lid to build the frame under the wood planks of the lid later on, which are nearly square in diameter (except on the outside following the wig-curvature).
  7. Slight rounding of the lower (foot) edge following the picture and for a more natural shape.
  8. First bevelling of the edges, cutting of the head part of the reconstructed lid since it is depicted by the SfM-model itself.
  9. Fitting the edges of reconstructed lid and SfM-model together.
  10. Bringing the frame part on the height of the visible squared timber of the scan, with an inner extrude on the thickness (based mainly on the scan, but also on a Late Period coffin lid, see Zygalski 2019, 146)
  11. Removing the innermost polygons to get a square diameter. With the frame as reference, deleting all polygons of the SfM-model below this frame (except the tenons).

Bibliography

J.H. Taylor (2009), Coffins as evidence for a ‘north-south divide’ in the 22nd-25th dynasties, in: G.P.F. Broekman/R.J. Demarée/O.E. Kaper (edd.), The Libyan Period in Egypt. Historical and cultural studies into the 21st-24th dynasties: Proceedings of a conference at Leiden University, 25-27 October 2007 (Leiden), 375–415.

A. Zygalski (2019), A coffin lid of an unidentified person from the Late Period. Observations on the wood and construction, in: H. Strudwick/J. Dawson (edd.), Ancient Egyptian Coffins. Past–Present–Future (Havertown/Oxford), 145–156.

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