Round in the square

Adding a round hole in the center of a square plate seems simple enough, but when coupled with the smoothing aspect of subdivision surface modelling, it can get a little confusing and frustrating to say the least.
But we're going to use the fact that the software averages out the vertexes, and rounds everything out to our advantage!

Here's a low resolution cube that was squashed a bit into a plate. The size isn't important for this task.

I've deleted the back face as we won't be using this at all.

I've added an edge loop down the center of the cube in both directions. This defines the center of the plate, and gives us some vertex edges we will use for our round hole.

And based off of yesterdays post, I've also added the edge loops really close the the edges of the plate. This will keep the corners of the plate sharp. And because I deleted the back face in the beginning, the edges that border that opening will stay sharp as there is no face for the software to average against!

Using the 'free tessellate' tool, I drew 4 more edges onto the face of the cube in a diamond pattern. If you use the shift key while in the 'free tessellate' tool, it will snap to the center of the edge your connecting to.

At this point it's wise to move the whole plate we made to location 0,0,0. This will aid in setting up the rest of the job at hand.

If we select the 4 points on the diamond, and look at the properties tab, we can see the overall size of the diamond shape. We'll be using this number for the next step.

Ive added a cylinder primitive with the default sections set to 8. If we smooth this cylinder, it will go round, so were going to use this as a template for our hole.

With our cylinder selected, we can change the size of it to match the numbers of our diamond shape I drew on the plate. Then we can move it to location 0,0,0. This will place it dead center of the plate.

Looking dead on, we can see the overall size of the cylinder is the exact same size of the diamond on the plate. We just need to add a few more vertex edges to our plate to get the hole shape we need.

I simply split the diamond edges out to the corner points. If you take the time to count, you'll see that every polygon still has 4 edges, this will smooth predictably for us. But we have a couple of steps left to our round hole.

Using the center yellow scale cube on the manipulator lets me move the 4 selected point outward at the same consistent rate.

We're done with the cylinder now, so I just deleted it. But now we have the lines we need for the hole.

We have 2 choices at this point. We can delete the selected polygons leaving the hole open, or we can extrude them back to create a pocket hole with a bottom to it. We're going to extrude them back.

Holding the ctrl key enters the 'extrude' mode. And then I simply extruded the octagon inwards. This is our low resolution pocket hole.

If I smooth this now, we get this shape. It's almost right, but not yet. You can see that the hole isn't very defined, and out of round, due to the low resolution.

I've added 2 new edge loops right close to the top and bottom of the hole. This increases the resolution at these 2 spots, which will keep the edges sharp.

You can clearly see that the hole is much more defined with the added edgeloops.

If I add one more edgeloop on the other side, so we end up with a loop on both sides of the hole opening, the hole will be very sharp and defined

Once we smooth it, it's held it's edge perfectly!

So in fact, using a SDS modeller like Hexagon, Blender, silo, 3ds max, etc, we can actually model anything from organic characters, to hard surface models like cars and appliances, with an exceptional amount of visual accuracy.

One of the renders we did a while ago featured this process for recessed set screw holes in a beer dispensing tap:

 This was all done in the computer, modeled in Hexagon and rendered in another software package.
There is no limit to the details that can be created by breaking big jobs into smaller pieces. I even modeled the threads that hold the tap handles. It was modeled at full size, so if the handle need to be fabricated, I can send the file to the manufacturer.

I think for tomorrow I'll pick an everyday item, and run another simple tutorial on how to model it.
8)
JWO

subdivision surface (a basic overview)

Due to the TV show NDA, and I can't post anything, I'm going to do a small summary on SDS modelling. This is done in our modelor of choice, Hex. This does translate over to any SDS modelling program, like Silo, Blender, etc.
There really is no "only way" when it comes to 3d SDS modeling. There are general guidelines for animation and rigging, but as we generally model everything in our final pose, most of that doesn't quite apply for us.

The first thing is understanding what happens when you smooth an object:

Heres a cube in Hexagon, pretty straight forward! Until you smooth it:

With 2 levels of smoothing, the cube is now a sphere?!?!? This may surprise, or even discourage people from using mesh modelling, but it's completely expected behavior.

When smoothing is applied (which blends all the faces into smooth surfaces) a mathematical process is calculated.

Here's the same cube from the front view

With 1 level of smoothing applied, every polygon is divided by 4, then the edges, or 'vertex' are averaged between the polygon right next to it. This essentially starts to smooth the surface out.

If I apply 2 levels of smoothing, our 6 sided cube ends up with 96 faces (or sides) Once we understand that this happens consistently, every time, we can start to have an immense amount of control over how our shape comes out. This is why we want to try and keep as many faces of our shape as quads. This means a polygon with 4 edges. Quads smooth predictably, every time. Polygons with more, or less than 4 sides are unavoidable, but keeping them to a minimum, or hiding them deep in a model, keeps our results predictable!

The cube we started with is actually considered a low-polygon model, or low resolution.
We can strategically add vertex edges to the cube to get it to hold it's shape when we apply smoothing. Essentially we will be adding resolution to our cube.

If we add an edge loop very close to the edge of the cube, the distance the computer averages the polygons is drastically reduced.

You can see the results quite clearly. The ends where the edge loop has been added have held their shape a lot better. A tad bit soft, but not a sphere. Because we didn't add any edge loops on the other faces of the cube, they rounded right out.

Now, if we add a set of edge loops to the other edge of the cube, we'll be adding resolution in the other direction.

This is clearly a step in the right direction. It's a little bit weird on the other side, because we haven't added any resolution in that direction yet.

I've added resolution to the remaining sides of the cube.

Now when add smoothing to the cube, the tighter resolution holds it's shape a whole lot more.

You might be asking why we would smooth a cube, adding all of those faces, when we started with a cube in the first place. The truth is, if you need a cube, then use it the way it is. But if this cube was welded into another piece of geometry, then that new geometry was smoothed, the cube would go spherical again.
Our last image of the cube has the edges and corners looking a tiny bit soft. The closer we move our newly created edge loops to the edge of the cube, the tighter the corners will be.

This always is the case, always. The higher and tighter the resolution, the sharper the edges will be.

Tomorrow, I'll show you how to add a perfectly round hole into the center of a square. Easy when you know how it works, frustrating if you don't know. Hopefully these little blogs will inspire you to give SDS modelling a try. Or help with any trouble you may be having understanding how it works.
When I started, I just wanted to know what was happening, and my frustration level was through the roof!
8)
JWO

Driving off into the sunset!

We got a last minute job Friday, so with the t.v show build in full swing, it was a weekend at the shop.
The last minute job was for a commercial, but that's all I know. They wanted a 13" blue cube. They were able to provide a Pantone number for the color, which happened to be the exact same color of the light blue PVC we use. As luck would have it, we had a sheet in stock!
It needed to be strong and lightweight, as they'll be writing on it and tossing it around.
I drew the file in Aspire, just 6- 13" squares. These got mitered on our mitering jig with the little Makita router.

With squares cut on our Techno cnc, and drawn in Aspire, I know that everything is dead square, making the assembly very easy. A simple tape hinge holds it all together until the glue got applied.

I reinforced all the edges with strips of 3/4" pvc, chem welded into place. For the final top piece, I used a medium bodied pvc cement, as the water thin stuff can evaporate to fast!
I never got a final image of it, but it was exactly like you could imagine.
That job delivered this morning, for shooting tomorrow.

--------------------------------------------RACECAR------------------------------------------------

Jody finished the paint job on the driver's body, and despite the rumors (Rob), it isn't actually Jody in the car :) Although.............................................................

He drove off at the end of the day. Who knows if he'll win the race, but he'll be looking sweet, whatever he does!
We should get this back in around a week, and I might brand it out with all of our amazing sponsors, for display. Maybe Jody can drive it to the market for groceries!
They added a bunch of signage for our current NDA  t.v.show build, so that should keep us busy for another week. YAY!
It's the gift that keeps on giving :)!!

8)
JO