Three-D Modelling for Railways

Available on cults3d ! Helping out on a layout at a show last week, the owner of the layout said he wanted a storage tank with a  set of spiral steps to get to the top. I realised that would be pretty easy to do with geometry nodes , just create one step, and then have it repeat in a circle, but as well as rotating, also increase the z-location. The tank itself is just a cylinder with a flattened hemisphere on top. I did one without steps, and also a bridge to link them. Here they are primed, but not printed, from about the same angle. I am - one day - going to build a "vignette" of a chemical site, and will use these, and will paint them accordingly when I do.

The 3d printer vat has a transparent film on the bottom through which UV light shines to form a layer; the model is then prised from the film before the next layer is formed. This film is a consumable, and the first one lasted me about two months, but the second lasted over two years. I had some issues with prints failing part way through, and could see resin on the screen when the vbat was removed, but the film appeared to be fine. I replaced the screen protector, but got more failures, and the screen was dirty almost immediately, so I am fairly sure I have a hole. As the film gets stretched during each cycle, a pinprick hole could get enlarged during the process, but be very hard to spot. So I replaced the film. I followed the Elegoo video , and there is no point me repeating it. This is the state of the film, not that bad after 2 years: The screen protector, after just two weeks: I had recently replaced it (see here ), and that was my last one. The cheap ones I ordered are coming fr...

I have recently been using the lattice tool more and more. It is excellent for gently deforming an object. A lattice is a primitive type in Blender. To add a lattice, go to Add - Lattice . Note that the default size is a 1 m cube, so half the size of the default cube. A lattice is a 3-dimensional array of points, and by default is just two in each direction. If you go to the properties pane, you will find it has its own tab, and you can vary the number of points in each dimension, from 1 upwards. In practice, there is not much point is more than five or so. Rather than x, y and z, it uses u, v and w, I guess because it can be rotated. On its own a lattice is not much use. You need to combine it with an object. To do that, add a modifier to the object Deform - Lattice , and then link to the lattice. You also need the lattice to be is the same location as the object, and completely enclosing it, So far the object will not be changed; select the lattice, and go into edit mode. Now move on...

I had an issue recently that prints were failing at the same place on the build plate. I posted this image on an Elegoo support group of Facebook, but the answers were not convincing. These are three identical models, but only one is failing, and when I did other models they failed at the same place. It is not an issue with the model, or how it is orientated, etc. It is also clearly not levelling as that would apply across the entire build plate if it happened in the middle of a print as the entire baseplate is at the same level - more likely the base would not print properly. I was worried the screen might be faulty - that would give bad results in just one region - though you would think it would give vertical holes where the pixels failed. So what about an issue with the film on the base of the vat? I emptied the vat, and it looked okay. Not perfect, but as good as it did after a few uses. What I did notice the screen had resin on it. I have not had a leak, but resin seems to get ev...

This is getting into minor details of Blender, and you can get by quite happily never knowing it. This post is more a way for me to record what I have discovered. The 3D cursor is a point in space in the Blender virtual world. When you create a new object, it will be created here. By default it is at the origin, and that is often fine, but occasionally you want to move it - perhaps to get it back to the origin because you moved it by accident, or perhaps because you are working well away from the origin. Certain operations use the 3D cursor as their centre, and being able to move it is help then too. Note that the cursor also has a rotation; I have yet to find a time when it is useful to change that. Here are the various ways t move the 3D cursor. Cursor tool Select the Cursor tool in the Toolbar, then left click where you want the cursor. I think it maintains the current depth. That means if you do this while aligned to, say, the x-axis, the x value will not change. If you are not ali...

Well, not right now, but what do you do if it does? And what precautions can you take in case it does? Note: This is about using Blender, not printing, which is a whole other level of horribly wrong! Save The first point is to save, and when you do something that could go horribly wrong, save first, and then savewith a different file name, and then do it! Blender keeps a copy of your last save, with the extension "blend1". You can set it to keep more old versions in  Edit - Preferences - Save & Load . Not something I have done, but it depends on your style of work. Undo The first thing to try is to Undo . Just hit [ctrl]-Z until you get back to where it was good. Blender counts every selection or unselection as a step, and you can quickly get to the Undo limit. I would strongly suggest increasing it to 256. There is a memory limitation so if you hit problems, you may need to reduce it. Go to Edit - Preferences - System to find the setting. I have once gone back 256 times...