Hard Surface modeling – smooth compound curved surfaces

[tommyboy]

New to ZBrush. I’m only on my third model ever! I decided to try to create a model of a pick up truck. I’ve been stuck on the fender flares on the bed sides for way too long. Decided to ask for help here. I cannot get them smooth enough to render as straight sheet metal with glossy paint on them. Every attempt comes out looking like it’s made of clay with slight variations in the surface that distort the reflections in undesirable ways. Am I missing something or am I asking ZBrush to do something it was not designed to do?

I look on the 3D model sites like turbosquid.com and see some perfectly straight and smooth pick up truck models that look like they are made of straight high gloss painted sheet metal though not necessarily done in ZBrush. Then I see other pick up truck models that look like they are made of clay and painted high gloss. Yuck!

My interest in 3D modeling is primarily for hard surface models of real world objects, rendered out like photographs in KeyShot. It has to look real. I don’t have any plans for making mythical creatures or game characters which ZBrush seems to be perfectly suited for.

I can make perfectly smooth geometric shapes with curved surfaces. I can also get geometric shapes to bend along two axises using the transpose tool and they remain smooth enough to support a highly reflective finish. But if it’s anything more than a simple two axis compound curve I don’t know how to keep the surface smooth. I’ve tried manipulating the verts individually on low poly meshes. I’ve tried using a dynamesh along with the move, planer and smooth tools. I cannot get the modeled sheet metal smooth enough.

Image of the part of the truck I’m struggling to recreate. Any suggestions?

[beta_channel]

The polish brush is your friend with hardsurface stuff btw.

[tommyboy]

Thanks beta_channel. You’ve drawn some red lines to represent a mesh. However, all of my meshes so far have been rectangular grids. Can I get a mesh like that in ZBrush? Tutorial link perhaps? Sorry for the scope creep but maybe a mesh with a flow of polygons that actually followed the shape would provide something I can polish and smooth in predictable ways without distortion.

[Cryrid]

For nice hard surface curves, it can help to keep the number of verts as absolutely low as possible. This puts the computer’s subdivision algorithim in charge of creating perfect surfaces with nice curves, rather than have you try and sculpt it all by hand (which as you’ve seen will lend itself towards imperfect surfaces).

You can still use the sculpting tools to quckly hammer out the overall shape and proportions, but from there I would switch to the Topology Brush or ZSphere Retopology in order to draw a new edgeflow on top of the surface (example). This requires some familiarity with traditional subdivision modeling techniques, since again you’ll be relying on subdivision to create the curves for you (while controlling the tightness of these curves by using manually placed control edges or creases). At this point the goal becomes creating an edgeflow built entirely for subdivision, not for sculpting (which is what the automatic solutions will strive for instead).

Dynamic subdivision will also be more useful at this stage, since you’d be able to make use of the zmodeler brush and other tools as well while still previewing what the subdivided result will be.

[dillster]

I probably would have kept that lower poly for longer, just to get the curves shaped before subdividing. If you still have the lower subdivisions, try smoothing the surface at a lower one using ZModeler and Dynamic Sub, and work your way up from there.

[tommyboy]

I’m developing a better understanding of the workflow required to create the model I want thanks to the suggestions provided. It will take me a little time to learn the new techniques and apply them. I’ll check back in later with results.

Thanks for the help.