VectorPaint blind mortise-and-tenon sections: fit a projection into a stopped cavity

English translation of the Chinese original, translated on 2026-11-13. Original publication dates, attribution, code and version notes are retained.

A tenon projects and a mortise receives it; attractive grain cannot establish their fit. Manually draw separated and inserted cutaway states of an invented blind joint in VectorPaint, retaining the cavity bottom and remaining material. These are no cutting, tolerance, gluing or load-design specifications.

Declare a stopped cavity and section convention

Use a 1600×1000 landscape canvas for separated and inserted views. The University of Melbourne workshop’s mortise-and-tenon description distinguishes an end projection and receiving cavity. Choose a stopped rather than through cavity; do not transplant fabrication instructions into this drawing exercise. Mark the removed section and rightward insertion direction, using light material and background or darker inner walls for the cavity. A cutaway explains a structure; it does not claim visibility through real wood.

Keep the tenon continuous with its parent piece

Draw the left rail as a rectangle with a narrower rectangular tenon projecting from its right end and shoulders above and below. Combined paths or ordered colour blocks may represent it, but the projection belongs to the rail rather than a floating third block. Hide grain to inspect shoulder turns and a gap-free root. Set illustrative length 300 and thickness 120 pixels. If precise entry is unavailable, place approximately against guides; an approximate drawing is not a zero-error fabrication plan.

Retain opening, inner walls and stopped bottom

In the right member’s cutaway, create a left-opening cavity with an illustrative 120-pixel thickness and 320-pixel depth, leaving material behind it. Distinguish upper wall, lower wall and bottom instead of pasting an unexplained dark rectangle onto a surface. Mark the bottom in an audit layer so insertion cannot accidentally turn the cavity into a through-hole. Darkness is a cavity convention, not a claim about actual illumination, and these pixels recommend no real tenon length or remaining-material thickness.

Align direction and thickness in the separated view

Align tenon and cavity centrelines with background between the pieces and a separate insertion-direction arrow. Compare thickness before comparing length 300 with depth 320; the illustrative difference is 20, not a recommended assembly tolerance. If one component uses a frontal view and the other an elevated view, fix the view convention rather than stretching the opening. The arrow indicates direction and must not resemble a solid pin through both parts. Do not introduce a third component absent from the design. The separation-view arrow must agree with the inserted-view displacement. Repair a leftward arrow paired with rightward insertion rather than exchanging component identities.

Preserve shoulder contact and bottom clearance

Duplicate both parts for the second view and translate the rail along the stated direction until its shoulders meet the receiving face. The tip stops short of the cavity bottom, retaining the illustrative 20-pixel gap. Hiding the outside cover should reveal a complete tenon rather than a background block that trims excess length. A too-long tenon belongs in a labelled collision control; deleting the bottom cannot make the valid joint fit. Shoulder contact and tip clearance are distinct. Do not push shoulders into the receiving member to force the tip to the bottom.

Keep grain and section marks separate from boundaries

Add sparse grain after validating structure. Horizontal rail grain and lengthwise receiver grain are pictorial choices. If hatching marks a cut surface, use one convention and explain it; strokes across the opening must not resemble partitions. Structural meaning, especially shoulders and bottom, must survive hiding decoration. In a labelled control fill the cavity as material and identify the changed space ownership rather than aesthetic colour. Keep audit labels so these illustrative copies are not delivered as construction plans.

Troubleshoot apparent penetration and truncated tenons

Open an exported PNG and enlarge the inserted view: check whether the rail colour hides the bottom or creates doubled shoulder lines. For apparent penetration inspect order and actual length before cutaway occlusion, rather than cropping the conflict away. A tenon changing from 300 in one view to 200 in the other suggests unintended scaling. Compare both against the same guide instead of relying on thumbnails. Open other export formats to inspect labels and cavity edges; extensions prove no path or legend accuracy.

Reopen and check projection, cavity, shoulder and bottom

Save, leave the canvas and reopen. Confirm that the tenon belongs to the rail, the cavity to the receiver, shoulders stop at the receiving face, and the bottom remains closed with clearance. Both states retain component counts and reference dimensions without added pins, glue or locks. Hide composition arrows or retain clearly explained ones, keep an audit copy and open final output before marking completion. Another reader should distinguish material, cavity and stopped versus through holes, without inferring real strength, machining precision, assembly feasibility or performance.