I have come to Carrara after a great deal of time with Poser, and love what the program can do (but would love cloth sim).

My problem is that I cannot get a fractal noise displacement to work with a vertex object.  Maybe I am missing something, but the program just locks up and won't even preview it.

I am modelling a simple lathed goblet (Carrara Pro 6.2 btw) as a vertex object.  I make it with a brass texture and the add fractal noise to displacement channel in material room.  No preview any more, and attmpts to render lead to a little box saying "error".  yet if I make the same goblet as a spline the exact same sequence renders very well.  But I cannot make a spline goblet that looks as decent as a vertex one, so this is very annoying,

Am I doing something silly here, or is it a bug?

One of the ways of modeling the object may be inherently setting up the object's UV's for your displacement map to use.

Also, how much smoothing does you model have before you enable displacement?  And is displacement adding even more smoothing of its own to the model?  And is your rendering doing even more smoothing, or is it set the same as the object's smoothing level?

How does the fractal noise look on both objects when applied just as a texture or a bump?

I can apply fractal noise to a spline abject, no problems there.  And I can apply fractal noise as a bump map, which warks fine.  I can even use the displacement paint tool on a vertex object...works a treat.  Just ant kind o pattern (cellular for example) used on a displacement shader for vertex objects stuffs the whole system.

Is this just me?  can others use fractal displacement on vertex objects with no worries?

Like Shonner said, with vertex objects and displacement, a lot depends on the level of subdivision of the mesh and the level of smoothing you choose for the displacement shader. Sounds like you have one or both of the smoothing settings up too high, generating an extremely hi res mesh which your machine can't handle.

smoothing only set to 1 on both.  Even if I turn it off...same thing happens.

I just tried using fractal noise on a vertex object in the displacement channel and it worked fine. Maybe you could post a wireframe of your model.

Stevelee, send a print screen from object and the displacement tab to us please.

Just a note: I applied a fractal displacement to the horns of the untextured millenium dragon. When I applied a color shader to the whole figure: KABOOM! The fractal spread to the entire figure in the preview, before freezing the program. So this may be an issue of interaction between the UV map and fractal displacement. (?)

Maybe this is a bug and need to be reported to the Carrara bug track so we can have it fixed in nect release;

system
Core 2 duo
ati radeon X1950XTX
2 gigs ram
WindowsXP

You may not be waiting long enough, somtimes Carrara is working on something and you can't tell. It seems locked up because there's no hourglass.

I have just tried putting the cube primitive in there, and that displaces fine.  Is there something about my goblets (they are lathed polylines)  that stuffs up the renderer?

Patrick_210.  No,  if I try to render the goblet it puts up a little sign that simply says "An error has ocurred"  but no more details.

You didn't post your displacement's Top Shader.  I'm guessing you can Turn off Displace in 3D View and set your video to Software instead of OpenGL and see if you can get past the calculations.

Pretty sure now that it has nothing to do with displacement itself.  After numerous tests, displacement shaders work fine on anything else (vertex or spline).  It just appears to be lathed objects that cannot take anything at all in displacement channel.  Has anyone else tried adding displacement to a LATHED vertex object.  I begin to feel it is either a bug, or something to do with UV mapping of lathed objects.

Found out the problem, and its fairly unbelievable. Nothing to do with UV, or smoothing or displacement settings:  if you lathe a polyline, once the  vertex object is finished, then before you leave the modeller you MUST delete the polyline which is still sitting on the working box.  After that the vertex object will take displacement shaders with no problem at all.

Not sure if there is a reason for this, or if it is a bug.  Thanks to all who suggested fixes.

A post of the VM room would better show us the wires than the Assembly room.  It's hard to tell what kind of object it is.   You may have to convert the model to a VM object so that you can smooth/displace.