Problems with extrude / creasing / ambience

so as 3D models get triangulated anyway for rendering, does triangulating add to the point/face count?

I usually try to minimise triangulation as the model gets harder and harder to understand visually!!

cheers for the info anyway, I will try this.



I know what you’re going to say – send you the errant model and you’ll take a look – but here’s the problem anyway!!

I had built up a model (of the tender of my Class A4 steam loco) using a primitive, followed by a subtract and then a series of extrudes / shifts and then some subtracts.

Then after a certain number of steps, extrude just seemed to hang up. You wouldn’t even get an unrecoverable error – 3DC would just hang – and show as not responding on CTRL-ALT-DEL

The only way out being to end task. 3DC does still helpfully recover the model for you but it’s on the irritating side!!

It’s definitely the model as it only happened on certain faces.

The face in question also seemed to be unable to maintain its ambience/specularity – being permanently in shade – both in 3DC and MSTS.

I thought that the creasing had been affected so I re-creased to no effect unless I reduced crease to 0 on the slider. Then the ambience returned, but on values such as 14 it was in shade.

I still have the affected model, which I will send you. The only way I got around the problem was by deleting the errant face and using solidify selection on it’s costituent points. This seemed to work, but I rather suspect the model is still corrupted – extrude still hangs for example.


I looked at the model and found the problem. The side that you indicated had too many colinear edges. If you triangulate it its should be OK. The lower face extruded OK on my computer after I triangulated the face above. I think it crashed for you because Direct3D didn’t like the arrangement of edges/points. The lower faces was very difficult to select due to the fact it has colinear edges also. What I did was I right clicked on one of its edges and then clicked andquot;Select-]Facesandquot; and deselected the faces I didn’t need.


I tried that and before optimisation it had 115 faces, 130 points. After it had 115, 128.

Still have extrude problems though. And shading problems. There do not appear to be any colinear points which aren’t needed as they form part of faces above the face in question.

Needless to say, object is in the mail for you!! It’s from v5.5 not 5.5a


It sounds to me like you may have a corrupt or partially corrupt object. It can happen that you get a face(s) that is made up of entirely lines or points which Direct3D (and 3D in general) does not like. Here is what I would do:

1) right-click on the object and select andquot;Propertiesandquot; and find out how many points/faces it contains. (write it down)
2) Use the Optimize operation on the object
3) repeat step 1.
4) try extruding and see if it is resolved.

Let me know the number of points before/after.

Also, if you have any edges that colinear (where a point effectly bisects an edge) you can have the shading problems. This will cause problems not only for 3DC but for MSTS and other programs. You can fix this by trimming away unneeded points.


Triangulation doesn’t add any faces or points and you can triangulate a single face.


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