Answer day - Civil 3D performance vs games

[Anonymous]

Hi

I've long wondered why Civil 3D requires so much power in terms of both CPU, GPU and Memory when moden PC games can achieve so much more with less hardware.

The data used in typical C3D models are (when broken down) mostly different variations of polylines, which have no volume/textures/Lightning effects. Of course there are som types of one dimensional data associated with them (lenght, x/y/z coordinates, rotations, direction, etc).

Then we have Pipe networks, who often are associated with 3d models, but rarely ever viewed in other ways that top-down and visualized by lines (outer/inner walls).

Surfaces from large areas of height data can naturally consist of alot of data. But if the games I play can visualize kilometre-wide areas with cutting edge Graphics yet with precision of details - I se no reason for C3D to be as slow as it is by just showing simple lines.

And Before you answer "Oh well games do alot of simplifications of geometric details, and other tricks", Think about if you perhaps should make C3D do the same thing. After all, all we want is a fast, responsive program to model geometries and 3d/2d objects. 

[fcernst]

Yes, I am wondering the same thing...

We are having performance issues with surfaces that we need to use for Hydrology analysis. Below is a 611 acre surface from LIDAR consisting of 4.2 million Ground points, and we essentially can't do anything with it due to the long hangs! 

The first task manager below below was taken as the drawing is hanging on extracting elevations to a feature line. Even just right-clicking on the surface hangs the drawing up. The second task manager is during a long hang on Watershed Analysis.

When I created the surface, Civil 3D said the surface "may be too large for a Civil 3D format" and created the .mms file.

Why is Civil 3D hanging up on a drawing of this size when only 902MB of memory is being used by AutoCAD (61% total more available on the computer) and only 32.9% of processor resources are being used?

We need to be able to handle these drawings smoothly and efficiently for civil engineering use.

File Sizes:

Elevations from Surface to Featureline:

Watershed Analysis:

Surface:

[dgorsman]

Fast and responsive means fewer options on what and how things get done.  Try it out - get a racing game.  Now substitute a shopping cart for one of the cars.  Whoops, not available.  OK, how about a RC toy car?  Nope.  Motorcycle?  Only if it's already programmed.  The data sets of games are tiny compared to civil data sets, and the use of that data is barely inter-related.

Lets look at it from the other direction.  OK, first order of business is dump the vertical nature and rebuild from the ground up.  Ah, there's a problem - referencing it in other AutoCAD-based products isn't going to work without some sort of export (cue Revit guys laughing here...).  Re-using existing content is going to require an import conversion.

And blahblahblah single-precision math, non-geodetic coordinates, "precise details" being faked just enough to fool the eye, blahblahblah.  You get the point.

Not to say it isn't possible - it certainly is.  However there *are* serious trade-offs to be considered.  Somebody will NOT be happy.