Hi Felix,

> Fortunately, it can read 3dm file (at least those from Rhino)
> hopefully it would be the same with Moi (I haven't downloaded
> Moi yet).

Yes, I think that 3DM files saved from MoI should work with BobCAD, also in addition to 3DM format MoI can also export to some other CAD formats: IGES, STEP, and SAT, all of which I believe are supported by BobCAD as well so there are several other ways that you could also use to get model data over.

But yes NURBS modeling alone is not ideally suited for generating embossed or relief type patterns, NURBS can generate curved forms but it's generally more focused on creating broader surfaces from curves that you draw and not on smaller more high frequency little bumps and things of that nature.

For shapes like you want to do where the base material is going to be like a plane, then a 2.5D mechanism that creates the model from a bitmap can be one of the easiest ways to generate those kinds of things, like BobArt or ArtCAM.

There is also a free tool called ZSurf that can generate a NURBS surface from a bitmap which can then be read into MoI, see this previous post for some more info on that:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3825.2

Then another possibility for doing those kinds of relief details is to use a brush stroke based deformation modeling system, like ZBrush or 3D-Coat. Those work in full 3D which allows you to do some kinds of sculpted shapes that a 2.5D process won't be able to handle, but it will also be more time consuming and take longer to learn how to use than the 2.5D type processes. But you may want to check out 3D-Coat in particular which is not too expensive, if the workflow suits you ok then using that gives you quite a lot of freedom for full 3D sculpting. It can also work well to use MoI in combination with a brush sculpting program, where you use MoI to build the simple base shape (with full CAD precision) and then import it into 3D-Coat and then apply bumpy details inside of there. That combination can work well because those brush based sculpting programs tend to be more oriented towards building figures and so they don't have a lot of precision type tools for accurate things.


Hope this helps give you some ideas to try out!

- Michael

Here's a very simple example. (I dont have any good "carved wood" examples, so i just did this really quick)

The good thing about BobArt, is it works with geometry and not just bitmaps... Some pratice on how to stack it and choosing the emboss method, like spline, can get you looking pretty good.



So here i emobossed from a solid to get my general shape (Lots of flexability here to create the base shape of the piece with a solid) Then with some 2d only geometry, I can add other shapes to that initial base.. This could be various curve types with raised and cut dimensions.

If I wanted to go very high end, i could create a leaf shape to match an actual leaf, then create the puff (like you see here) with that shape, then apply a texture with a bitmap, which would have it be an actual leaf... (Time consuming and would require breaking it down into indivual jobs)

Anyway, if any of this intrest you, we could explore it more... Maybe some actual curves that you have??? If it vbecome too much of a BobCad thing, we could move it over there also...

BobCad file linked to here:

http://www.i386group.com/moi/bobart_sample2.zip

Hi all,

I'm impressed by all your suggestions and especially by your efforts. Hopefully, all this work was done not just for me.

I think I have found a fairly good analogy to express what I mean when I say I don't like to use such and such programs, I do a little bit of programing from time to time and though it is quite possible to write a windows app in strait C, I think anyone will agree that it is much easier and much less time consuming doing the same app in C++ or easier still (in my case) with Visual basic.

I'll admit also that at this time, I don't really know what I'm going to do in the near future. Currently, I'm doing mostly things like this http://latelierdefelix.com/ArmopireBassCaro.jpg or this one http://latelierdefelix.com/ArmoirePointeDiamant-10-finl.jpg.

Practically, all the details on these two are done by hand and all the finishing product are homemade. Yes, I know, I'm crazy, especially considering the time it takes and the price I got for them. Though I love doing this kind of work and it makes me feel good I basically get paid minimum wage if not less. The only good thing I realized is that my work comes up on the first result page of a google search. So I though of exploiting this by creating some kind of virtual showroom to show what I can do. And while at it I might as well think of something to get a pay raise. So I thought of adding carved details to my work but instead of doing those by hand I thought of using a homemade 4 axis CNC. Also, since I have no idea of the market for this kind of work, I would like to spend as little as possible. This is why I'm here at the Moi forum, at $300 compared to $1K for Rhino, I think I can afford it at this time even if MOI as a bit less features then Rhino, it seems easier to use. All the work I would do is for my own use basically and at this time I don't think I'll ever do some production type of work. I'm more in a custom and unique type of work mood but we never know.


wzhang, your designs are very nice and I like the idea that they could be done in MOI. Especially since such floral details could be something I would put on my own design. Fortunately for me, such details are just that, details, in your case, these details make or break the whole object. If you add the fact that they would be done on wood with a CNC the end result would probably never be as nice and clean as yours and I can live with that especially that I wouldn't like my work to look like I used plastic wood pored in some mold. I'd prefer by a long shut that it would look like hand made. I even thought of using the CNC just for roughing and finishing by hand.

Thanks to every one, I think I'm going to like this place very much.

Regards,
Felix

Burr,

please don't put in to much effort in this, it would make me feel bad. I'm a fairly old guy and it takes me more time then I would like to learn new stuff. But I can see from post here and others that MOI is an excellent program and it seems fairly easy to work with.

With all the replies to my post, I have plenty of work on my plate for now.

Regards,
Felix

edit: Sorry I missed your second post!

Hi Felix,
my example didnt take any time at all, dont worry... The point of my example was basically showing the result with only "2d curves"...

The last 2 pictures you showed would be done easy with MoI alone as solids....This would be your best bet.. The previous ones, that showed leaves and things more like "Vines" or branches and stuff, could be acheived with the 2d geometry and BobArt... Good luck.

"Although STL can be sent to you CAm package and machined, it will be linear at some type of resolution."

With the exception of some high end machining software like Delcam, very few 3D cam packages send anything other than linear data to the CNC machine. Sure, a CAM package may import a nurbs model, but most likely its not sending spline coordinates in G-code to the machine. So starting with a polygonal model is somewhat irrelevant if the polys are small enough so they won't be seen in the finished piece. And that, of course, is also related to the material, tool size, feed rate, spindle speed, etc.

The toolpath is calculated from the original NURBS surface, and in this particular CAM package, you have options of the tolerance that the toolapth is calculated off of.. The polygonal model would be dictating the staight lines and breaks and the calcualtion gets very heavy fast, on a polygonal model... The NURBS surface is far more desirable...

A toolpath would choke on a multi-million polygonal count, where it would be a breeze on the same NURBS surface, to acheive the same "curvature resolution", at say, .0001.

I just made a simple curved NURBS surface, then created a polygonal model from it.. The 3dm file is 17.9 KB and the STL is 62.6 MB. The toolpath caluculation on the 2 was 4 seconds for the 3dm file and 4 minutes for the stl...

Hi Michael,

thanks for the info, lots of stuff to digest and sorry for the delay.

Though I'm not sure yet, I think this 2.5d mechanism as you call it, could be the way to go for many if not all the details I would want to add to my work. I have both Rhino evaluation and ZSurf4 and tried a couple imports into Rhino. Following zsurf suggestions, I managed to obtain a decent looking shaded view. But the same file loaded in BobCad looks like the "meshing" is way to coarse and of course I have no idea how I could improve that in BobCad. I finally downloaded the no save version of MOI and imported the same file and I was surprised that it looked much better then in the other 2 programs. But I'm curious to know which programs renders the most faithful representation of the true relief surface because that's the one that will be carved by the CNC? The same would be true with 3D printing I assume.

As a suggestion, a MOI trial version something like the Rhino 25 save version could be ideal to explore the full potential of MOI without the pressure of a deadline.

In this post here http://moi3d.com/forum/index.php?webtag=MOI&msg=602.8 I found a paper about UDT (Universal Deformation Technology) as implemented in Rhino 4 and if I understand all this correctly, it would be more then enough for the kind of stuff I want to do. Is there by any chance something equivalent in MOI? Say for example I've created some kind of an embossed medallion on a flat surface in ZSurf and I'd like to kind of "apply" it on a cylindrical object and make it an integral part of this solid object.

edit: I found my answer, Zsurf can create the "bump" surface on a cylinder and other forms directly. Then I suppose MOI can deal with the rest of the modeling to create some solid.

I think what I'm asking is should I go with MOI or for Rhino especially if one thinks a bit long term. I wouldn't want finding out later that trying to save some money today I end up spending more tomorrow.

Many thanks,
Felix

Hi Felix,


If you're loading the same .igs file into each one, then each one actually has the same true surface data to work off of, you're just seeing differences in the on screen visual representation of the surfaces. MoI just happens to have a particularly nice on screen realtime display.

3D printing is a pretty different process than CNC cutting - for 3D printing you will generally need to output an STL file which is made up of triangles, and whatever is exporting from the IGES surface to triangles will have some controls to control the density and it will probably be done at a fairly higher density than the on-screen display is showing.


No, MoI does not have any equivalent to those UDT tools in Rhino right now, but it is an area that I want to add in MoI in the future. Those tools in Rhino can definitely be useful, and there are several people that use Rhino in combination with MoI to have access to those particular tools in Rhino.

But it sounds like you also found out that if you want the Z-Surf result wrapped around a cylinder you can do that with an option in Z-Surf for that particular case instead of needing to use Rhino UDT.


Well, Rhino is more difficult to use - it's set up to be most comfortable for people with an AutoCAD background. If you have spent a lot of time with AutoCAD before then it's an instant great fit, but if you are not familiar with AutoCAD then some of the things in Rhino will probably feel pretty odd and kind of archaic like the command line interface.

MoI is more oriented towards someone who may not have a lot of prior experience in CAD and so it has a lower learning curve and is generally easier to use.

It can be a good strategy to start out with MoI and then also add in Rhino later if the additional tools in Rhino would be useful for you.

It's definitely worthwhile to spend some time with the trial versions of both of them to see what feels the most comfortable to you.

- Michael

Michael,

I appreciate a lot your thoughts on choosing between MOI or Rhino, there seems to be some wisdom in what you say.

I've been trying Rhino for a little bit now and unfortunately for them it keeps crashing on me and they imply it's because of my video card. This may be true or not, I don't know, I just know every other apps. I've tried don't crash, so I'm a bit skeptic. I'll give myself the time to learn as much as possible on MOI before making my decision.

The only observation I can make about MOI at this time is that there is no layers and since "drawing" a complete piece like the "armoire" will require quite a few parts, I know by experience the screen will become over crowded and this can be a problem. But since I have BobCad I'm thinking already of importing each part created in MOI and create a single layered model there. If you think of a better solution please let me know.

If I understand correctly NURBS are basically mathematical objects and as such the resolution and or precision of a true surface is only limited in theory by the numerical precision of your computer. But in practice, for displaying or when some meshing is required (which must be almost all the time) the resolution and or precision must be limited by quite a bit such that it can be processed in a reasonable amount of time.

Regards,
Felix

Hi,

I'm very impressed with my first real trial of MOI. After viewing a few videos from Pilou, (yes I speak french) and reading some parts of the help files, I realized the following in less then an hour.

Unfortunately, I've opted for the no save version so this is just a captured image. CAN I CHANGED THAT TO THE 30 DAY TRIAL?

There are a few things that I don't understand and I'd like your input. Observing the object (hi zoom) in the viewport, I see a lot of jagged edges almost as if there are hole in the adjacent surfaces, are these just display artifacts or something else? The reason I ask this is because I want to render object like this and would like the result to be nice and clean. There are also some part of the surfaces that look as if the normals are not right, if such things exist in NURBS. This object was build by joining surfaces and beside its name it says it's a joined surface, is there some way to make it a solid, if so, how?

May be this next question is more for Burr, now I would like to add something like a medallion centered in the middle of the curved surface, say something like on the top of wzhang nob for example. From previous posts and readings, this could be done via Z Surf but I'd like to know if there are some alternative solution that could be done directly in MOI especially for relatively simple geometry. For example, I could create the outlines I would need on a flat plane or a cplane, project them on the curve surface where I want them, then create the required profiles and use the appropriate construct tools to add volume, etc. Say that I do just that, the result would be like the medallion was just applied on the surface and not be part of the object, wouldn't it better to say make a hole in the surface, I forgot that I could possibly union the medallion with the object. I'm asking all these questions because I'm thinking of both the rendering and the toolpaths generation steps. Lastly, there is always the option of creating the medallion in BobCad/Art in part or in whole.

I think I'm looking for ideas on how one should or could proceed to do this kind of work maybe some kind of workflow. Are there "good" books one could read to kind of self trained on 3D design strategies with the idea of building the actual object?




Thanks,
Felix

Hi Felix, For the question part to me, you have described exactly what to do!!! I would model the medallion on the pillar the way you describe. The only reason to use Zsurf or BobArt, is if you are needing some kind of "Very organic" type of look or surface... Like a tree limb "WITH BARK".

Your model is nice. Yes, it should read "SOLID" if the surfaces were well formed and joined properly... If it reads joined surfaces, then those gaps most likely exist.. For me, the fastest way to learn MoI is the 3 tutorials that come with the help file... Michael covers many aspects, even basic NURBS modeling is learned from these.. They are very nice to watch. Short, concise and packed full.. Not painful like other video tutes.

Hi Felix,


Actually, MoI does have a layering mechanism, it's called "Styles" in MoI since it is a grouping mechanism that controls the visual color of the objects assigned to it.

To use it open up the scene browser, by pushing this button in the lower right area of the window:



That will open up the browser pane, and then you can go to the Styles section, which looks like this:



There are various actions that you can do in the scene browser like hide or show an item slot by clicking on the eye icon, selecting them by clicking on the text part of the item's line, assign selected objects to a particular style by clicking on the swatch rectangle, locking, deselecting, ... See here for some more complete info on it:
http://moi3d.com/2.0/docs/moi_command_reference11.htm#scenebrowser

When you export to BobCAD, the styles assignment in MoI should translate to layers assigned within BobCAD.


Yes, this is correct - a NURBS surface is what is called a "spline" - it's a mathematically curved surface.



It depends on what particular operation is taking place - it needs to be meshed for display because a display mechanism needs to use your video card hardware and video cards only deal with triangles.

But other kinds of calculations like surface intersections or booleans will use numerical techniques that interact directly with the NURBS surface.

- Michael

Hi Felix, it looks like you're off to a great start!

An answer to this question:


Yup, the no save trial and the 30-day trial are separate things, you can have both installed on your system at the same time.

Just when you install the 30-day trial don't put it in the exact same folder that you've already installed the no-save version, and then you can have both of them on your system.

You don't need to do anything special to change to the 30-day trial, you just download the 30-day trial installer and run it - it's a separate installer from the no-save trial version.

- Michael

Michael,

many thanks for all this info, especially the layer equivalent in MOI ie. styles and for the info on both version.

I want to mention again that I'm very impressed by MOI. I consider myself to be very newbie at this time and I can only imagine how productive I'll be with more experience.



Is it the same for sweeps, lofts, etc? I know, I'm a very curious guy and I figure that if some operations are more like math function and others are more of an iterative type, the result of these ops. may differ in relative quality. For example, I notice the 1 rail sweep I used seem to proceed by strait line segment to approximate the curve part of the rail. If this is the case then I would ask is there a way one can "control" the step size or would it preferable to use another operation if possible of course.

I use a join operation on all the surfaces of my shape and MOI reports it's a joined surface and not a solid as I would have expected. Would it be better to use a Boolean union instead?

Another observation, the rails I used are made in 2 parts, a strait line and a some spline I would believe joined together. When I select the original rail it's all selected but when I try to select the edge of the sweep surface, Moi select only a single part at a time. This behavior makes me curious to understand what's going on.

Regards,
Felix

Burr,

thanks for your input though I think I messed up bit. I requested your input because of your knowledge of BobCad/Art. What I was trying to say about "drawing" the medallion is yes I could use Z Surf especially if it's "organic" and it could be done in MOI if the geometry is relatively simple as your example, maybe using the method I describe earlier and what I didn't really mention is that it could be done in BobArt as well.

I think I answered my own question in a way and I'm sorry I bothered you with my self questioning.

Regards,
Felix

"A toolpath would choke on a multi-million polygonal count, where it would be a breeze on the same NURBS surface, to acheive the same "curvature resolution", at say, .0001."

An older machine with a hardware controller would choke on that, but it also would not be using splines either. With a modern PC based CNC controller, the file size is irrelevant as long as the PC can send the data fast enough to the machine.

Of course using smaller linear moves increases the file size of the toolpath. However, just because the toolpath file size is large does not mean it cannot be machined sucessfully. Perhaps your system uses arcs and straight line segments? Using arcs would account for a smaller toolpath file size.

Can you post some of the G-code?

I'm speaking about "Generating" the "toolpath", not the gcode that comes from it or the actual cut at the machine. The program that he is using tops out at around 100 MB... (Trying to bring in a 100 mb + STL usually doesnt work, let alone, toolpath it..)

Yes, the software he is using has a "fit arcs" selection, which will turn a 30,000 lines of code file into a 6,000 line file, but again, this is not really the area I was refering to...

Hi Felix,

> Is it the same for sweeps, lofts, etc? I know, I'm a
> very curious guy and I figure that if some operations
> are more like math function and others are more of an
> iterative type, the result of these ops. may differ in relative
> quality.

Loft is something that's calculated directly, but Sweep does go through an iterative fitting process, in a way the sweep is kind of like an automated loft that cooks up a bunch of profiles starting with a small number and measuring how accurate the result is and adding more profiles until the generated shape hugs the rail curves to a small enough distance.

But the error of such iterative functions is checked, in MoI the refinement will continue until the result is accurate to within 0.001 units.


> For example, I notice the 1 rail sweep I used seem to
> proceed by strait line segment to approximate the curve
> part of the rail.

Well these iterative methods actually produce curve output, the curve just gets more control points in it as it gets more refined.

The only way you should be seeing straight line segments in your sweep is if your rail curve is actually made up of straight line segments instead of being a curved shape itself.

Can you please post an attachment with the 3DM model file of your sweep so I can take a look at it and see what you are referring to?


> <...> or would it preferable to use another operation if possible of course.

Well, which tool is best really depends on the situation a lot - it would help a lot if you would post the model file to give some more specific context to what you are describing.


> I use a join operation on all the surfaces of my shape and
> MOI reports it's a joined surface and not a solid as I would
> have expected. Would it be better to use a Boolean union instead?

Well, that again depends on what particular problem you're running into - do you possibly have a surface missing leaving an open hole in the model? If so then for a situation like that you need to model a surface that fills in that hole and then join that in as well in order to make a fully closed skin. If you could post the 3DM model file that has your non-solid joined piece in it, that would help me to give you some more specific advice.

Boolean union (and the booleans in general) are more oriented towards intersecting objects with one another and removing some material from them. So for example if you have 2 cubes that are partially pushed through each other you would want to use boolean union which will intersect them and remove the area that is on the interior.

If you have a set of surfaces that all touch each other at common edges, where no material needs to be removed from anything then that's when Join is the right tool and not boolean union, although boolean union will often work the same for that, it will just try to do a lot of additional work to intersect things as well though.


> Another observation, the rails I used are made in 2 parts,
> a strait line and a some spline I would believe joined together.
> When I select the original rail it's all selected but when I try
> to select the edge of the sweep surface, Moi select only a single
> part at a time. This behavior makes me curious to understand
> what's going on.

Could you please post the model file so I could load it up and take a look at it?

If you have a rail curve that has sharp corners in it and is also not a planar shape, then that can cause the sweep to be made in individual sections along each smooth piece in between the sharp corners and you can end up with several disjoint objects from the sweep in that kind of a case.

If you have sharp corners in your rail and all the rail segments are on a single shared plane, then it will do corner mitering to make it all one piece.

But if you can post the model file that would help me to see what you're running into - it's really pretty hard for me to guess just by a written description because there are quite a lot of different things that can cause different results to be generated...

- Michael

Hi Michael,

at the time I wrote message 4123.19 I had only the no save version but I downloaded the 30 days version. Since I had to start from scratch I tried a few different things. Instead of creating the faces 1 by 1 and joining them into a close volume, I used booleans ops, a 2 rail sweep and I used a fillet instead of the 1 rail sweep.

I haven't finish what I wanted to do but I uploaded the new file as requested. This new version doesn't present the same qualities as the jpg I shown previously. Basically, we can't compare the two, this one seems much better and MOI reports it's a solid. Also, I deleted most if not all the construction items I used but if you try to select edges around the fillet or the sweep you will see that only a single part of a edge can be selected at a time and this may add a bit of complexity if further operation are required, unless of course if there is way to rejoin those parts into a single element.

I understand that it must have been pretty difficult to figure out what I meant from just a few line of text and a jpeg. I apologize, from now on, I'll supply a file.

Out of curiosity again, I can foresee the need of say warping a rather simple shape like the (flat) medallion in my file to fit on the curve part of the post and I think it will most likely be most of the time on cylindrical shape like in this case, do you think it's possible to write a script to do just that? Before you even think of it, I'm thinking of writing it myself of course but I would just like to know if you think it's possible with the currently available MOI JavaScript classes, methods, etc?

Regards,
Felix