As most of you know, I'm taking care of EMW's rapman 3d printer while he's off in the US. I managed to get it up and running after a fair amount of effort (the car ride over was not kind to it..) and have printed a few bits to replace broken and likely to break components.
Printing new bits for itself is all well and good, but at some point you probably end up with a machine that works and sufficient spare parts for some peace of mind. At this point you start to consider printing other things.
Of course, there's a whole Thingiverse of stuff other people have made out there, but I from time to time dabble a bit in very old versions of Lightwave, and I'd quite like to make stuff go from the byrnisphere to meatspace (sounds worrying to me too on writing...).
Unfortunately things are not as simple as they could be. Lightwave saves lwo files and Skeinforge (which takes a model and turns it into commands for the machine) takes stl files. But wait! Lightwave can export obj files, and Skeinforge can read them. Easy.
No. Nothing I made, even a cube, would be accepted by Skeinforge. So I tried a few more things...
Its probably worth mentioning that the remainder of this post will be (arguably more) boring and is mostly there as an aide memoire (pretentious no?) for me.
To take a model from Lightwave 7 (yes, I know, there are a lot newer versions out) to plastic reality you simply need to do the following:
1. Load Lightwave Modeller and load the model in question. At this point its a good idea to check if the model will print well - any sort of pronounced overhang will not print, as there is a limit to the bridging capacity of the machine. In this respect it is unlike a lemming.
2. Make sure you've installed the plugins from the plugins folder, and go to file->Export->Obj.
3. Download and install MeshLab. Its free. Open the obj file. You should see it render the object, without texturing. Go to File->Save as and save it as an STL file.
4. Optional (but reccomended for complex models). Download and install AccuTrans 3D. Its not free, but is available for a 30 day trial. Load the STL file.
Now, there's a button labeled water tight check. Its under help. No, not the blue help, the white one. This will check if the model is watertight, which is a requirement for Skeinforge to calculate commands to create it.
5. Theoretically, load the file into Skeinforge. However, its worth mentioning that for some reason the objects are 1000 times smaller than they should be. Oh, and the axes are reinterpreted at some point. So don't load it into Skeinforge. Go back to the internet for more stuffs:
6. Download netfabb Studio Basic. You could download the professional version for 99 euros. The Pro version generates the commands for the machine itself, skipping Skeinforge entirely. Anyway, assuming you haven't done that, open the stl in netfabb. You may well see a big warning triangle with an exclamation mark in the bottom right corner. Ignore it for now.
7. Go to Part->Rotate and select 90 degrees, X axis and OK.
8. Go to Part->Scale and type in 1000. You might need to go to view->Zoom to->All parts to see the model. It should look like the part you started with.
9. If there is a big warning triange in the bottom right of the render display, there is a problem with the mesh. If not, skip straight to step 11. Luckily there is often an easy way to sort this. The third icon from the right on the bar under the menu should be a red cross. Click on that. The render view will change.
10. At the bottom right there should be a set of tabs, with Status selected. Click on "Automatic repair", then execute in the dialog box that appears. This may change how the model looks. Then click "Apply repair" in the bottom right. When prompted to remove old part, say yes.
11. Hopefully (fingers crossed) the warning sign has gone. Now you can save the fixed file by going to part->Export part->STL.
12. Load the file into Skeinforge. At this point, I'm going to assume you know how to do that. You should (with the default settings anyway) see a 3d view unhelpfully from dead above and a slice view you can step through to see the path the head will take.
13. Try printing the part.
Does it work? Probably. I've done all but step 13. While I was messing around with this I decided to change some cross tie bocks and threw the machine out of whack. Should be easy enough to fix once I finish blithering on here, but its too late to run the machine now in a room both above and below a bedroom. It will have to wait...
to be concluded ...