Jagged edges instead of nice smooth edges on Rendered model

[strangedj]

Hello All!

New to the forums, had a quick search for my problem, tried a few things and got nowhere.

I'm using AutoCAD 2005 and have constructed a 3D representation of a gas pipeline stopple arrangement (a section of pipe is diverted under pressure to carry out repairs or tie-in new pipe routes). The 3D model has been constructed using mainly revolved surfaces, but there are a few small solids in there (hand wheels on valves and wooden skid blocks).

I've set up viewports in paperspace, the main is a plan view of the mapping and route lines, in 2D, then there is a smaller viewport with an orbited view of the 3D model.

When I render the 3D model, I see jagged edges where there should be smooth curves, diamond patches where there should be fillets or weld-neck flanges, and the pipes look a bit gnarled too. I've changed FACETRES, ISOLINES, SURFTAB values, tried photo-real versus photo-raytrace, discarded back faces, had shadows on/off, I've exhausted all the different variables and still come up with a less than desirable finished render. I'm just wondering if there's anything obvious that I'm missing, or if any of you have found a set of shading/rendering/smoothness variables that produce good results every time?

There's a sample .jpg here:

Sorry for the large picture, but if you zoom in to a valve or a bend, you can make out the poor quality I'm coming across.

Any help would be most appreciated.

[jaberwok]

Hi.
For the items that are meshes, it may be worth setting Surfu and/or Surfv to higher values - that has a similar effect to creatiing the parts with higher Surftab1 and Surftab2 values so will give a "tighter" mesh. Personally, I'd create as much as possible as solids but note that your Viewres setting will affect the results - the higher, the better - within reason.
It may also be worth setting Hideprecision to 1 (= high).

[strangedj]

Hmm, I tweaked all the settings again, plus the ones you mentioned John (thankyou). I'm wondering if my graphics card is up to the task, or some other hardware problem (not enough memory maybe). : (
Even with isolines/surftab u/v/1/2 set as 32, hideprecision is set to 1, antialias is set to med.... well without going into the full details of all the settings I've tried, basically I get the same blocky render each time. It's almost like the renderer is seeing the model through diamond-shaped frosted glass. I'm going to try my home graphics card (NVidia Geforce FX) and 1gb of memory tonight, see if it is hardware related, as my work machine is on-board graphics and only 512mb RAM.
Then I'll probably try modelling it all in solids, as you say John, and see if that makes a difference, although the bends were modelled from solid torus, then sliced, but it's those same bends that are rendering all gnarly-looking.
Watch this space...

[strangedj]

Okay, I seem to have sorted it out. I basically scaled my 3D model up from real-world units (ie 257mm dia. pipe) to 4 times larger, rezoomed my viewport to suit, and hey presto, it worked, smooth render. Happy once more )
It seems that the renderer doesn't render minute detail too well, or that something else is amiss in my drawing, maybe because I work in metre units (ie .257 units dia. pipe) but this seemed to solve the tesselated edges, and rendered the fillets smoothly. I think I'll probably use millimetre units in future for this kind of render, and scale my viewport to suit. I've a feeling this problem was material related though, as the wireframe and gouraud shades looked fine.