Converting a NURB Surface to Polygon Mesh problem. (Softimage|XSI)

[Adam]

First let me say that I'm going to be asking for help here often.

I'm trying to learn Softimage|XSI to get a head start for Half-Life 2. So I can add my own kinds of dynamic props to my maps since Hammer won't be enough anymore. So many things in XSI compared to Hammer that it gets confusing trying to get a handle on everything thats going on with having to worry about selection settings, view settings, interface modes, what is, and is not currently selected in the view ports, what options are enabled for each tool, etc. and one little thing wrong in any one place can make nothing work the way you want, it's a little overwhelming, but I think if I keep at it, it will all make sense and become second nature. Much like Hammer is for me. (Of course I been using Hammer since 1998, and I still learn something new every once in a while.)

Onto the question:

I noticed that whenever I convert a NURB Surface to a Polygon Mesh, not only do I get a Polygon Mesh out of the conversion, but apparently I'm left with the original NURB Surface as well. Shouldn't a conversion operation leave me with no duplicates, clones, or anything? I mean, it acts like I did a 'Duplicate to a Polygon Mesh' operation. (If it even exists which I doubt.)

What makes things worse, is that when I try to delete the NURB Surface since I don't need nor want it, the newly created Polygon Mesh is deleted with it, even though I had only selected the NURB Surface.

I'm starting to think the conversion operation not only kept a copy of the original NURB Surface, but also took it upon itself to perhaps include the Polygon Mesh as a child of the NURB Surface, so maybe a heirarchy is causing the deletion of both even when the other is not selected.

I appreciate any help on this matter.
Thanks

 

[Noodlygod]

=) Hello again. Try it again with that immed button clicked. Or after you've done the conversion freeze either the original or the mesh, maybe both. (Theres a freeze button near the immed button) The way I understand it is that anytime you make a boolean, conversion or subdivision you need to freeze the shape, otherwise it will continue applying the properties of the parent to the child. Anywhoo let me know if that doesn't work. Good luck!

 

[Adam]

Alright, thanks again, im trying it out now. By the way, what does it mean to make a boolean? I thought a boolean was a datatype in a programming language that denoted true or false and in machine code as a 0 or 1 bit?

 

[Adam]

Thanks alot, I entered into Immediate mode like you said, and I froze both the NURF Surface and Polygon Surface, and then when I deleted the NURF Surface, the Polygon Surface stayed!

I would just like to know why this was not mention in the official tutorial I'm following... I'm doing every single step excatly like it says (Tutorial 3: Polygonal Modeling - Boombox) and yet they did not mention this extra step at all. I guess they don't try out their own tutorial before releasing to the public.. :/

 

[Noodlygod]

Hehe, I dunno why they don't mention it. I know I found it somewhere on their site or in some tutorial. I just started not too long ago with XSI myself although I've had experience with other 3d software. I'm not certain why it's called a boolean but you're right about the programming bit.

 

[softmonkey]

When you do (nearly any) operator in XSI it retains its like back to its generator object.

In your case the link between the polymesh and the NURBS surface still exsists. Try this:

Create a NURBS surface
Poly.Mesh>Nurbs to mesh
Move some points on your NURBS surface

Result: Polymesh also moves.

If you want to stop this behavior you can work in immediate mode, but it is much more flexible to just press freeze (bottom right of the interface). This will break any links you have.

You can get into some advanced stuff by expanding your polymesh in the explorer and freezing parts of your constructing history.

TOP TIP: Never freeze a model with and envelope operator on it. You will lose your envelope operator.
If you want to add some more geometry to a model you have already enveloped, find the envelope operator in the explorer and right click on the icon - choose disable from here. Model you stuff and then freeze. Then re-enable the envelope. Yey!