See inserted replies, please:

Peter Popov wrote:
> 
> As I understand it your complex model was made up of patches, most
> probably using moray or spatch. You are using windoze 95 (at least for
> newsreading) so here's a windoze-only workaround: from spatch, export
> your model to some polygon format (ex. vrml). Then, convert that to a
> pov mesh. Then use uvpov to slice up the mesh since it treats meshes
> as csg-able.

Yep, there is one little sPatch piece in it, used 6 times. Thanks for
the work-around idea however it already is a bicubic_patch anyway, not
the same thing? (I know very little of these things). Though it was
messing up before getting to any of them. It looked like I had a decent
slice going at first with a plane, I think it was, then maybe messed up
at the bicubics. Keeping textures and all from what I could tell. I was
doing quick tests at low resolution. Then upon some changes, using a box
instead, I failed to get anywhere near the same result.

> There is another problem with this method and I have not yet found an
> universal solution. Since the plane (or box or whatever) used for
> chopping gives the resulting surface its own texture, the result is
> either a monochrome .df3 or a black .df3 :) (if no texture is given to
> the plane). Suppose you've modelled a nice blob with separate element
> textures, and you want to see the inside of it. No way, Jose. Sorry.
> That's the reason I went a little off topic and gave up trying to
> model a mushroom cloud density with blobs (the original poster's
> question). Modelling is easy, but making the .df3 out of it is a pain.

Yeah, I know what you mean, but I know I had colors of the original
model showing properly at first, as I said :)
 
> There's a method that works for csg unions, though. Instead of slicing
> the union with the plane, slice each part of it separately and texture
> it afterwards. This may be quite a tedious work, but a macro might
> help, like:
> 
> // suppose your cutting plane is caused sliceObj
> 
> #macro Object ( myObj )
>   intersection
>   {
>     SliceObj
>     myObj
> #
> 
> Invoke it like this:
> 
> Object ( niceCSGableObj ) texture { coolObjectGuts } }
> 
> This will save... um, some time ... at least.
> 
> Man, this *is* an ugly macro, I know, but it should work.
> 
> Now, I summon all gurus: gather around and try to make up a way to
> show the cross-section of a blob keeping its internal textures intact.
> Here are some suggestions to try out:
> 
> Use a bounding (not clipping!) object that incorrectly bounds the
> blob.

I did try clipping with a box inversed. And was using orthographic
camera. I don't quite follow your "inside" idea, however 'direction no
longer applies (nor 'angle') with this camera type, only 'up' and
'right' do.

> Use a weird orthographic camera setting (some combination of location,
> look_at and direction which is beyond my skills) so that the screen
> plane is *inside* the object. Will this work?
> 
> // object fits the unit sphere
> 
> camera
> {
>   location -4*z
>   look_at 0
>   direction 4*z
>   orhographic
> }
> 
> One last question: how about slicing objects with media and getting
> correct results?

I do hope you mean slicing an object that has media, instead of use a
object with media to slice up another object.
 
> I've asked these questions before, but now 1) I am narrowing them down
> 2) there are more povers around and 3) pov skills increase with time
> 
> I can't test the stuff right now as there's already a line waiting at
> the computer (I hope dad doesn't notice the slowdown... I put POV in
> the  system tray and then intentionally hung explorer, so the tray now
> only holds a clock and a volume control :) ).

Bad boy!

> ---------
> Peter Popov
> ICQ: 15002700

Well, trial and error always prevails. It's that error part that bugs me
most.

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