The HammerAn exercise in 3D modelling and texturing

This is my first attempt to make something with Hexagon. I got it because it seems to have tools that none of my other 3D modelling wares have. The texturing was done in Blender.I decided that I would start with something simple, so I went out to the shed with my camera and got what I thought was a simple shape: a claw hammer. Note that you should read the manual first (I'm not going to go into all the basics here) and that I used Hexagon 2.5 on a Macintosh G4 1.25 Ghz twin processor machine, and that not all features worked exactly as per the manual. That's reality, folks.

PreparationI began with pictures of the hammer. These would usually be first altered to load into the program but for this job I did not do much to them as I wanted to keep things as simple as possible.Here's how they look loaded into Hexagon:

Note that they don't line up or match in scale – for a more complex modelling job you would need to fix both of these first. Hexagon didn't care that they were not square but you may need to switch on and off the tickboxes for the images to get them to appear at times.

ModellingI began by making a circle which was then flattened on it's top, bottom and sides so that the shape matched the end profile.This circle was then scaled and moved until it lined up with the side view.Next, I extruded this profile several times to make the basic handle shape.

The Universal Manipulator works well for this task, and when you click on one edge line of a ring and type “L” you can then move or rescale a whole ring of edges (loop) at a time.I then realised that the end where it joins onto the head would need some serious work to get it to fit – this is where round becomes square, never an easy thing to do, so I left it for later and went on to the second part of the job.

I then started on the head with a hexagonal type shape which I then filled and extruded to make the main section, and created the hammer “punch” bit with another circular extrusion. All fine so far, but now the trouble starts. First, realise that once you have boolean joined two parts, it is a pain in the *** to adjust the meeting of those parts after booling so get them as close to perfect joining as you can before you join.Second, joining two parts where the bits you don't want all disappear inside the shape (as in this case) is the easiest boolean. Here's the two head parts before fine tuning and booling:

Now here they are after tweaking and booling:You can see how close I managed to get the edges before booling.

I needed to tweak the top of the rings to a close match – to repeat, the closer you can get the parts before joining, the less trouble you will have afterwards since the booling process often adds lines or triangulates quads (as you can see above) which you will not enjoy trying to move around. Having made the face of the head where the handle meets it, I could now duplicate it and extrude it to make the part that would merge with the handle.

Okay, I admit that I was foolishly optimistic thinking that a new program would do booleans much better than my older ones – despite several attempts, I just could not get the round-to-square shape on the end of that handle.

The answer? Simplify the problem.

I ended up chopping the whole handle down to a conic shape and booling it with a simple trapeziod to get the right shape.

This meant that I had to remake the rest of the handle afterwards, but it worked . . . . well not

at first. Here's the second problem you should watch out for:

Here's my two simple parts ready for the bool.Looks okay, right? Wrong. This what you get when you bool it:

Look at the blue area – the circular part didn't quite go past the edges of the square part.You don't want to spend the next half hour trying to clean up messy corners like this – and

more importantly, your shape will not be neat and symmetrical by the time you finish.Once I fixed that up and tried again, I got this:

I left the claws until last as this proved to be quite tricky too.First, I tried various curves traced off the pictures and then attempted to extrude it to make a shape, but his did not happen: to extrude you need a face and I had not even closed the

bottom of the claw shape. Next I tried a polygon but this was no better: it had too many points on the curve to get a smooth shape.

In the end I made a new line splitting the top of head down the centreline (which would be needed later anyway) and the extruded the top face several times, using the handles to tweak the loops until it looked about right. Here it is in process:

This made one claw, and then it was a matter of completing the cut all the way around the head, deleting the half of the shape with no claw (including the bottom disc) and mirroring the remainder to get the full head.

I then welded the two halves together once they were aligned – but to my surprise, the edges would not weld automatically, I ended up welding individual points together to get the edges merged properly before I could replace the bottom disc. This was not good either – it means that the shape isn't actually a proper circle any more, but perhaps next time I'll get the weld

perfected.

Finally, after a little more tweaking of the shape the modelling was finished – now to colour and render it.

Hexagon is not a rendering program – if you want a nice textured picture of your model you need another program. I use Blender because while others charge scary amounts of money for their software it's free and it has enough features that work well on my computer. It's also fairly good at modelling but not as good as Hexagon – for example, bevelling in Blender bevels all the edges of a shape equally, whereas Hexagon lets you do only one edge at a time.

BLENDER – Adding the texturesFirst, I tried importing the whole thing into blender as an OBJ file. This meant that the whole thing (handle and head) obstinately decided to make itself into ONE unit rather than the two pieces I had carefully done in Hexagon, which I thought did not help with my plans to texture the two shapes differently.

I'll skip the details of making the texture maps up - you can mess with that yourself, it's not hard if you have an image program like photoshop or gimp.

Blender does permit multiple textures but I hadn't even found where the buttons were for them before starting this project.

I started by selecting the points of the handle and then went to the texture buttons, then to the image tab and then hit the “Load Image” button.

Then I return to the buttons and hit the materiel button, then found the map input tab and used the buttons on it to set the texture mapping on the shape.

I then hit CTRL-I to reverse the selection of points on the shape and did the whole thing again

for the other texture.

All this was not bad except that the first time I didn't find the map input tab. This meant that when I went back to the first set of points to change the mapping it covered the whole shape with one texture, and despite several attempts I could not get it to behave.

Finally I worked out how to get it right: just select one or two faces of the texture you want to change, make the changes to the mapping and the rest of the texture will change to match without the annoying whole-shape-one-texture thing happenning.

Here's the faces of the head selected in Blender

Below is the finished model rendered in Blender – it could still do with a bit of tweaking but it's good enough for my first attempt.

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I still didn't quite get the shapes smoothed out and the textures could do with a little adjustment – but maybe next project I'll get those details sorted out.

Another thing that I should point out here is the whole geometry thing: take the round bit of the hammer head as an example. Maybe you could make the head and claw, then mirror it and join the halves, then bool the round bit onto the rest of it last, thus getting a perfectly round head – but that's assuming that the boolean works smoothly on a more complex shape, which it may not.

For the hammer, precise geometry is not all that much of a problem (the original is quite roughly made) but other things will need circles to be circular, squares truly square etc. and you need to be able to put everything together the right way for this to be the result – so first, before you start modelling, you need to analyse the shapes you are making and work out a plan for their creation.

This is complicated by the fact that some operations such as booleans need to be done on small parts of the final shape, so if you wanted to make a shape with several holes in it you will need to “cut” the holes first in smaller sections of the final shape, then join all the parts together in a later step.

A newcomer to the modelling craft might think that using a boolean to cut from the circle to the square section was too much work – perhaps you could just delete points until the end was square, right? - except that would not be the actual shape of the real thing. I made a point of modelling a real object because it is easy to throw together fictitious stuff from shapes and just say “That's okay, it looks good” - but making something that looks like a real object is much more of a challenge, and much more worthwhile in my opinion.

Prof_Nullhttp://www.prof-null.livejournal.com/October 2008