You may have seen elsewhere that coming up I have a test build for an LNER D2. The first build is to be a BR period build and I have a J6 chimney casting from Gladiator for it. However once the etches are proved I plan to build a second D2 for myself which I wish to finish as it was in it's early life with the LNER in lined green. This means that it will need the original chimney so I need to turn one/have one 3D printed or something. Those who are Gauge O Guild members my be aware that following on from the success of the virtual shows the Guild has been hosting some special interest session in various subjects one of them being 3D CAD/Printing. I missed the initial session a few weeks ago but caught up with it via the YouTube channel and then joined last nights session. Prior to joining the Zoom session I downloaded and installed Fusion360 which is the software at the centre of the 3D CAD element of the sessions. This morning I had a play and following a demo video done by a fellow GOG member last year I managed to draw a chimney. Having completed it I shared the image below with the gent who ad created the artwork for the D2 etches and he commented that the smokebox looked a bit narrow. Then it dawned on me that I had used the figure for the radius taken from the drawing and hadn't doubled it to enter the diameter. Apparently you can enter a radius figure but I haven't worked out how yet. So this afternoon I attempted to redraw it using the correct smokebox size. You will note in the image above that there are orange coloured squares. These are offset planes that I used to apply the dimensions from my chimney drawing. I managed to miss out one of the planes (for the bottom of the chimney rim) and try as I might I couldn't manage to draw any lines between the planes like I had this morning. in frustration I deleted all but the base, saved it and went and had my dinner. This evening I worked out how to import a drawing, resize it and then draw over it as I would in Inkscape or QCAD. Below are a couple of views of the revised drawing. I am now a happy bunny. I haven't got anywhere near the skills of our very own Andy or Paul but it's a start.