modeling awith sPatch

sPatch  is a nice spline based modeler. I really like that modeler because it doesn't overflow you with thousands of functions but still provide the necessary tools to create interesting objects. Because it is spline based it especially good for bio shapes and curvy objects. Moreover, it can export your work as VRML, DXF or POV files. The latest is especially interesting cause the output is not a triangle mesh but a union of bicubic patches, which means the curves remain smooth during rendering. But a quick tutorial being worth 1000 pages of words ... let's get busy and quickly model a nice and curvy object! mmmm ... I feel thirsty somehow ;-) so lets create a bottle of coke! 

Phase 1: 

I open a new document under sPatch.   I set a value between 0.250 or 0.100 for the grid .   Then I enable the grid.  Now using the add tool  (pressing A key to gain time), I draw a rough profile of the bottle in the XY plan. The XY plan is important because I will use the lathe function later. For this bottle I use a closed profile because I want to be able to vary the apparent thickness of the glass. This profile need not to be extremely accurate but I make sure that the two point making the middle of the base are on the Y axe. This is  because the lathe is made around the Y axe and I want a seamless junction there.   To avoid that my future lathed surface self intersect I use the peak tool to alter the profile near the Y axe. Now my profile follows exactly the lathing axe so my surface will be OK.

Phase 2: 

Now I disable the grid.  I use the translate tool  to fine place the points forming the profile. I use the XYZ switches to make sure I don't move the selected point in an unwanted direction. For instance, I disable the X axe when moving the two points that I want to remain on the Y axe.  If necessary I use the add tool  again to include new points in the profile curve. I use the group tool to select multiple points and move that selection around. Especially when I'm happy with the shape of the neck I can move it around as a whole. Notice the variation of thickness that I can achieve with the closed profile.

Phase 3: 

I change the lathe setting to a fairly high and even value (something like 30 or 32).  Then I use the lathe tool  to generate the bottle from my closed profile. Notice on the left that the obtained shape doesn't have the right proportion.  I select all the points (Ctrl-A) and use the scale tool  with the Y switch off to make the bottle thicker or thinner. I also use the scale tool  and the translate tool  on group selections  to obtain a satisfying shape.   A shaded preview show that my bottle doesn't look bad but is still too smooth. It lacks these characteristic grooves to really be recognised as a coke bottle.  Note: Use the view tool present on top of each view frame to navigate between views and to switch between the shaded and wireframe mode.

Phase 4: 

I now want to create the relief on the bottle surface. To achieve this I need to apply the scale tool  to specially selected points. These points are on the outside and where the bottle seems to be swollen. I only select every other point around bottle as shown on the left.  Tip: selecting these points is the only difficult part of this tutorial. My method is to select all the point at first (Ctrl-A) then to use the group tool  to deselect all the unwanted nodes. Splitting the window into 4 views can help as you can use the easiest view for each point.Note that deselecting numerous points with a rectangular tool is a bit tedious so I really can't wait for Mike Clifton to add a freehand or polygon based selection tool (please, pleeeease!).  I switch off the Y axe and scale down this selection very slightly to obtained the wanted groovy aspect. I make sure the scaling is small enough to avoid the inner surface to intersect with the outer surface.  The shaded preview now show a much more convincing coke bottle with grooves that catch the light and create nice highlight and reflections.

Phase 5: 

Just to explore the possibility of sPatch lets try to make this bottle melt under the very very very hot sun of Scotland!?!?! ;-)  I select only the neck of the bottle with the group tool . I then use the rotate tool and the translate tool on that selection. Then, using the group tool I add the circumference just underneath the neck to the current selection and re-apply translate  and rotate .  I repeat these three operation till my selection include the entire bottle except the base. At this stage the coke bottle look quite melted but still a tad too regular. Checking than I don't create intersection between inner and outer surface I use the noise tool on the current selection to add some more natural variation to the curves. The shaded preview looks good to me ... and the rendered version with pov look even better.

That's all for this first tutorial. Next one will explain how to model ..... I don't know yet! ;-) 

Add-on note: This tutorial was the result of my first experience with sPatch. It generates a large number of patches and I don't recomment you try to render a scene with several of these bottles under POV unless you have lots of RAM.