Hello Michael, I have only recently started trying out the MOI package that I won as a prize in the Turbocad Challenge last year, and have an example in mind that I would like to try to get started.

I am trying out some still life work in Turbocad, and would like to try a tablecloth with folds or wrinkles draped over a table, but with flat areas where other objects sit on the table, such as a vase, bottle or bowl.

Any examples of how to set about it would be appreciated.

Here's a 2 curve loft table cloth.

Thank you for your example, I understand how you have done this, but what I need to know, is how I get the folds on the top also, with some circular or other shape areas, which are flat where a vase or bottle, jug etc would sit.

Here is a link to an example of what I am trying to achieve, although more extravagant than what I need to get started.

http://www.turbosquid.com/3d-models/life-spot-light-ma/313824

You can create a curve with a number of points in it, then sweep it to get a surface with points you can pull..

That is more like what I am after, so will have a bit of a try with this method first.

Thank You for your input!.

Hi Mike, it looks like you've got some good tips on how to proceed.

But just a general note - usually things that have a lot of little lumps and bumps in them tend to be more in the domain of a sub-division surface polygon modeling program and not so much in the area of a CAD type program.

MoI does have some various freeform surface creation tools which may work for what you are describing, but really a polygon modeler is much more focused on making those kinds of free sculpted lumpy type models.

- Michael

Or for kind of wavy things like your example above, a brush based displacement type modeling program may even be a better fit than a sub-d polygon modeler.

You might want to check out Sculptris: http://www.pixologic.com/sculptris/ - that allows you to paint brush strokes onto a base object and then makes raised or lowered areas where your brush has gone over, it tends to be a better tool than NURBS modeling for doing organic lumpy type stuff.

Usually NURBS modeling is better for stuff that is somewhat more structured and is more defined by some set of profile curves. Things that are all lumpy and bumpy are not really very well controlled by just a couple of profile curves.

- Michael

Thanks for the feedback Michael, I have a free version of sculptris that I downloaded last year, so must have a try that also. When I received MOI as a prize last year, I did try some odds and ends out, even to the point of plugging your work to IMSI, in the hope of some similar features in some future version of Turbocad. I think that CAD is eventually crossing the line to more organic modelling which I welcome.

Just read the first snippet on Turbocad V19, which is going to have something they have called an SMesh or smooth mesh which can be created from a solid or surface, and has a number of mesh smoothness settings.

Here is the link to the article if it is of interest.

http://paulthecad.co.uk/on-the-way-turbocad-pro-platinum-v19/#more-1687

Hi Mike,

> I think that CAD is eventually crossing the line to more
> organic modelling which I welcome.

The difficult part is that organic modeling tends to need a totally different set of actual tools than CAD modeling. The overall process and workflow is pretty different - CAD work is more about drawing 2D profiles and then using those to build surfaces or cut away material, and organic modeling is more about manipulating a cage of 3D points and working with that big pile of points efficiently.

So it's quite a big task to try and unify them in one program without that program getting quite complex and sort of "bloated" by having multiple different toolsets within it that operate largely in a separate way from each other.

- Michael

Hi Mike,

> Just read the first snippet on Turbocad V19, which is going
> to have something they have called an SMesh or smooth
> mesh which can be created from a solid or surface, and
> has a number of mesh smoothness settings.

Looks like it's a sub-division surface which is a polygon modeling technique to work with a rough polygon cage and then produce a smoothed down polygon result from that.


That article you linked to says: "All Boolean tools can be used on Smeshes, as long as they are combined with other Smeshes or TC Surfaces."

So that sounds like for example you won't be able to do a boolean operation directly between a regular NURBS solid object and an Smesh object - it's kind of like there will be 2 different worlds that don't really inter-operate that much.

That kind of "separate worlds inside one package" can often lead to a lot of confusion, with stuff like some tools only being designed to work on one kind of object and not doing anything to the other kinds of objects.

If you want to do that kind of sub-d modeling, most likely a dedicated sub-d modeling package like Silo, Hexagon, Modo, etc... is going to be a better fit for that.

Things can get more interesting with sub-d modeling in CAD if the sub-d surfaces can actually be converted to a NURBS solid instead of only being treated as a totally separate polygon object type.

- Michael

Even the regreted Amapi who mixed Polygon in a same program and nurbs don't transform Polys to nurbs! ;)

Yes, I see what you are saying Michael, it says that there is a switch between solid and Smesh in the object properties, but do not know if it can change back to a solid after it is converted to an SMesh.

I downloaded the free version of Hexagon offered at Daz3d, and to my surprise, it has some very handy features. I am more used to solid modelling, so my surface modelling and it's variants need some intensive study.

I like where you are going with MOI, an excellent creation that really grabs the imagination.

Hi Mike,

> I am more used to solid modelling, so my surface
> modelling and it's variants need some intensive study.

Yeah unfortunately polygon modeling in particular is pretty different from solids modeling, so it requires developing a whole new skill set to be productive with it, even if you're going to be doing it within the same program that you are already doing solids with.

The fundamental task of poly modeling is about managing a big cage of 3d points and keeping them nicely organized into a smoothing-friendly topology.

NURBS surface modeling is a different thing yet than polygon modeling - NURBS surface modeling (like Burr shows above) is more about drawing profiles and then constructing surfaces from those. That works well if your object is actually defined well by a smallish number of profiles but objects that contain a lot of small sized details in them like little bumps and lumps (like what you showed before but also things like a human nose or ear fall into that category as well) are not really "defined" by a profile curve. You can get a profile like a silhouette of a human face, but you can't easily generate a face from that silhouette alone because the face's shape is changing in all kinds of small localized ways as it comes away from that silhouette.

Then the brush-based displacement modeling systems like Sculptris, Zbrush and 3d-coat are another different organic modeling approach yet, and they actually tend to have a lower learning curve than regular point-cage-manipulation type polygon modeling.

So anyway, there are several different kinds of categories of surface modeling.


> I like where you are going with MOI, an excellent creation
> that really grabs the imagination.

Thanks, I'm glad you like it!


- Michael

In Turbocad, you can change a solid to a surface, and in most instances a surface into a solid, only problem is when you convert a solid to a surface, it has faceted sides, and if you the change it back to a solid, you end up with a solid with faceted sides. The big advantages in cad would be a surface or SMesh representation of a solid, which would require far less memory to manipulate.

Hi Mike,

> only problem is when you convert a solid to a surface, it
> has faceted sides, and if you the change it back to a solid,
> you end up with a solid with faceted sides.

Yes, but that "only problem" is a huge problem because having your entire solid model turn into a solid model with flat facets will usually pretty much destroy your model. After you've done that you've basically lost many of the nice properties of solids modeling, stuff like having actual precise spheres and cylinders and all of that stuff.

Also since now your solid model is itself faceted, everything that you export to will think that the model is actually supposed to be totally faceted so you'll get flat shaded appearance in renderings, etc... Having a solid model that's made up of all facets is not good, unless it is supposed to be physically faceted like a diamond or something only made of boxes.

Getting a bunch of facets as your solid model is not the same thing as making facets for exporting to a polygon format like OBJ - polygon files are supposed to be made up of facets. Solids modeling data is supposed to be made up of broad curved surfaces, stuff like one sphere surface for a spherical piece of the model, etc...

- Michael

"""""""""Even the regreted Amapi who mixed Polygon in a same program and nurbs don't transform Polys to nurbs! ;)"""""""

Well, it DOES have this command in it, but it was very limited and pretty much only worked with Planar type faceted data.. Anything actually curved surface type would crash the app.

Another 'draping' method http://forum.alibre.com/viewtopic.php?f=52&t=9139 using blender... I don't know if it helps... Read from post #7

I had a look at the wrapped cloth link, and found this blender YouTube video, amazing what can be done.

http://www.youtube.com/watch?v=v_fLoZ74fnc

Michael, I have been trying some of the different tools out in MOI, and am fascinated, I have saved as sat in Turbocad, which appears to give the best results when opened in MOI, done some editing and boolean's, and saved the sat from MOI, and find the profiles are spot on when opened in Turbocad, smooth as. One of the main problems with complex lofts or sweeps in Turbocad, is solids cannot self intersect on the path, but MOI does not appear to have this restriction as far as I can tell. It would be nice if solid modelling engines would allow re-entrant solids, by overwriting the existing solid information as it intersects itself. I have tried a number of the tools out, and the network surface is very interesting, and will be of great use to me. You have got me hooked.

This week, I have tried Daz 3D Studio, Bryce, Hexagon, Sculptris, Moi, and am about to have a dabble with Blender also.

Lots to learn with the new tool sets and methods, but MOI will be a great addition to my software collection.

Many thanks for the feedback and links everyone.

Mike Geraghty.

Just found some updated information on the new Turbocad SMesh Michael, it looks very promising, an SMesh can be converted to a solid.

Here is the information that is starting to be compiled for Turbocad V19 documentation.

https://docs.imsidesign.com/display/TC19UG/Converting+a+SMesh

If this works out as well as it is described, a major movement in the interaction between the two modelling methodologies.

Hi Mike, I'm glad that you are getting more familiar with MoI!

> One of the main problems with complex lofts or sweeps in Turbocad,
> is solids cannot self intersect on the path, but MOI does not appear
> to have this restriction as far as I can tell.

MoI will not prevent you from creating a self-intersecting surface for stuff like sweep or loft, but it can cause problems later on to construct things like that. It's ok if the only thing that you're going to be doing with the surface is to export it to make a rendering, but if you're going to be doing more modeling operations like things that involve surface/surface intersections, those will usually not work properly on self-intersecting areas of surfaces.

Basically a self intersection on a surface causes a solid that contains that surface to no longer have a distinct inside and outside region and so things that depend on a clear difference between inside and outside will get confused by such shapes.


> https://docs.imsidesign.com/display/TC19UG/Converting+a+SMesh
>
> If this works out as well as it is described, a major movement
> in the interaction between the two modelling methodologies

It seems to be saying that it will generate a faceted solid though - if so then that's not really going to be a viable solution except for certain special case type shapes that are actually meant to be faceted in their accurate representation, like a diamond gem or boxy stuff.

In general a solid that is made up of a zillion little triangle facets is not the kind of structure that solids modeling methods are set up to work with.

- Michael