Not sure, but there might be something wrong with your construction method.

Have you tried constructing your half circle another way?

Draw a circle using the Ellipse tool with Shift held down.

Then direct select and delete the left-hand anchor. No need for scissors.

genot

They are 3D shpere renedered in Illustrator that s what they have in common!

To the OP please select your object and then show your appearance panel while the object is still selected.

It would bee hard to tell what your appearance for the object is if it is not selected

Like such see the pth is selected that shows the actual appearance of the object.

Do you undersand now Gernot?

You clearly have the 3D Effect applied to the layer and not to the contents of the layer.

look a little deeper and you will see the problem click on the contents whie the object is selected and see what you have there.

Jacob: That little blue square right of centre must be the centre point of the half circle. I can't replicate the black spot on CS3.

Yes, using your dimensions I get the same result. CS5 Mac 10.6.8.

Peter

Edit: The phenomenon kicks in at 1866 pt.

Edit: Except when it's a higher value than that. The shape of the spot varies. Spot grows toward a circle as diameter increases.

These are both at a diameter of 1866 pt., with default 3D revolve settings. Half-circle has black fill, no stroke.

I want to see a screenshot of the object slected and the contents of the olayer visible in the Appearance panel, I say you havce another effect applied at the object level and not at the layer level.

It kicks in at 1866 pts Really in orderr to get something the size of the OP's screen shot it would have to be something like 60 Inches.

I say hey have another effect applied.

If not then they haven't told us much and it seems odd that they showed us in the OP the 3D window without the preview checked and the Appearance panel with out a selection.

Then they show us a sscreen with it selected but only show us the effect applied to the layer but not what is applied to the object and then the reponse to you query is evasive.

So I have doubts about this if you can see my point.

Let them post the dimensions along with everything else and then we can see what is causing this rather than hide the info we need.

Emil's right, even a slight perspective change cures it, and resetting the perspective value a few times even lets you bring it back to zero without the return of "The Blob."

BTW even a .001 change in the perspective eliminates the circle and it will but it will read as being set to zero.

this is the part of the OP that is misleading

Everytime I make a sphere,

I got distracted by Gernot's comments and did not notice the 2000 pt dimension.

I believe this is a known issue, however even if you pointed out that you need a 2000 pt size I think your first comment made me think this was not just this time but all the time regardless of what size you use.

So true I could have read it better but perhaps you could have clarified it as well.

You will find on the forum that some of the contributers relate to soem posters and not to tohers this goes for the two that were able to asisst you as well, it is just a question of how each individual understands the others.

I often relate to users that the other two do not and vice verse. Just the nature of the internet.

And thaat does lead me to the same conclusion it leads you too I would be of little assistance to you as I will probably always read your posting in a different way that you intend it to be read.

No doubt in my opinion that you are correct avbout this I will definitely not comment on your postings regardless of the nature of it. I will post to threads tht are not posted by you even if your are contributing.

All the best to you