topic Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion in Fusion Design, Validate & Document Forum

Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

mavigogun — Wed, 03 Oct 2018 22:40:09 GMT

At first glance, Fusion offers a cornucopia of tools for getting stuff done- and that's a real problem. A cultivated impression of capacity is developed that works against design success- especially for new users; having not stepped in all the pitfalls and bear traps, the initiate and veteran alike are subject to project derailment when presumably firm foundations crumble. This circumstance is compounded by a no-Fusion-manual policy.

Two examples.

First- and one I'm not intimate with -is the Primitive creation tools (Box, Cylinder, Sphere) accessed via the Model > Create menu. I understand a number of tool failures present that will break Parametric workflows- what Fusion is all about -amongst other unforeseeable liabilities, such as inconsistent reporting of locations. These tools risk spawning workflow failures to the extent most Expert Elite users react to their employment as one might the planned marriage to a sibling.

The second example provides visual clarity. The BRrep to T-Spline Conversion tool produces forms that are only tangentially related to the parent. As example, I've Intersected a Cube and Sphere to produce a non-symmetric fractional "orange slice":

Let's Convert some of those surfaces from BRep to T-Spline, examine the results. I'll Convert the curved face later; I'd like you to image NOW how that curved section of "orange slice" will appear as a T-Spline form for later comparison with the actual product. First, a flat face:

As you can plainly see, Fusion has no capacity to Convert curved Edges- a primary asset in the T-Spline/Sculpt workspace! The 3-sided, curved Profile is translated to 4 squares. Unequivocally, a "dumb" tool. Can the shape be produced using T-Splines in the Sculpt workspace? Sure- and even with the T-Spline-preferred 4 sides. The best thing to be said about this lack of capacity: it is readily evident the moment employed. A lack of capacity or failure of other tools- such as the aforementioned Primitives -is often several steps removed from the when or where the tool was first employed.

Now let's see what happens when we Convert the curved face. Recall what you imagined it would look like? Good. Now regard the actual product:

The selected area in blue is the Face from our orange slice; the product here is an entire sphere! As a secondary issue, notice the unasked-for sphere suffers creasing of a face near the visible nexus of slices.

I've come to understand that a number of basic tools for confronting T-Splines are missing from this toolkit. "Fewer tools- that must make for an easier new-user experience, right?" Not at all, as users are left attempting to achieve results suggested by what is possible without the benefit of the right tool- a bit like trying to use a hammer for all your carpentry needs, or pilot a car that starts up, no problem- but lacks breaks or only turns left. (one might reason such a hypothetical car would feature label would be prominently

So, why care? What are the consequences? For new users, a gross misapprehension of capacity is likely. For moderately experienced users, X time is lost when workflows break. For expert users, Fusion is relegated to a tertiary role in favor of tools with demonstrated capacity and reliability.

A few solutions are self-evident:

create a comprehensive tool manual inclusive of the state-of-the-art, including failures, incapacities, and work-arounds
employ beginner, intermediate, and expert users to comprehensively alpha test tools before releasing them to the public
re-balance priorities toward reliability AND fulfillment of tool-suggested capacity

I suspect developers reflexively curtail their use of Fusion to the confines of their intimate knowledge of it's failures and limitations- an unrealistic condition for most users attempting to practically employ the tool kit.

I include here a screencast of the Conversions:

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

cekuhnen — Thu, 04 Oct 2018 00:17:15 GMT

@mavigogun

Interesting find - the T-Splines results are indeed pointless.

But I think the main reason here is one should know that T-Splines is based on quad polygon meshes and not on trimmed surfaces.

BREP to TS to BREP works well when the conversion is done with clean square BREP surfaces.

watch this screencast.

https://drive.google.com/file/d/1dHyf_jyQrMhdIS1FYxFuN8H6EqcdtfXD/view

I find very often people underestimate 3D - it is a massive and complicated topic.

Thats why people love sketchUp so much hahahaha

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

michallach81 — Thu, 04 Oct 2018 06:16:29 GMT

If you like to drive a car, first you must learn how to do it... same applies to t-splines, looks tempting to use it? Try to learn it first.

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

mavigogun — Thu, 04 Oct 2018 07:05:10 GMT

@michallach81 wrote:
*nothing productive*

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

michallach81 — Thu, 04 Oct 2018 07:20:42 GMT

Recently I've advised you to start one of your design form beginning, with another one I've said that everything is wrong and you should learn how to articulate your intent, did you've listened???

You blame others way too quick.

We have no right to expect form Fusion devs to lead users by the hand.

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

mavigogun — Thu, 04 Oct 2018 13:25:05 GMT

@michallach81 wrote:
Recently I've advised you to start one of your design form beginning, with another one I've said that everything is wrong and you should learn how to articulate your intent, did you've listened???

Your presumption here, as in that previous post, is both off topic and a misapprehension. As I wrote before, "everything is wrong" is not actionable advice- for anyone. You aren't confronting work, but ego- and there's no utility in that. I welcome constructive contributions when you choose that course.

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

cekuhnen — Thu, 04 Oct 2018 13:50:43 GMT

@mavigogun @michallach81

Gents chill 😉

Mavi while I agree with some of the concerns in this thread you used two bad examples that cannot woke well because they would require trimmed surfaces which TS does not offer hence why I made the video

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

michallach81 — Thu, 04 Oct 2018 14:06:23 GMT

The point I'm making is that your designs (to an extent you've allowed us to see) reveal significant flaws in your workflow or lack of skills. You're not in a position to make demands. Topics I've replied you were blaming Fusion for your own mistakes. You can report any bug you like or point flaws in Fusion, just don't go step further and stop making comments about Fusion dysfunction, and its development (https://forums.autodesk.com/t5/fusion-360-design-validate/open-letter-to-dev-stop-integrating-new-features-and-fix-what-ya/td-p/8024996).

Calm down, Fusion is less problematic than you think, just give it a chance.

Last thing, don't take anything I say personally, I'm just arguing with what you are saying and I don't like demanding attitude.

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

PhilProcarioJr — Thu, 04 Oct 2018 15:52:28 GMT

I think there are many ways to interpret critism...you can take it personal or you can use it to learn from.

Although I don't agree with @mavigogun choice of words to describe the lack of functionality in Fusion I do get and agree with his point. @michallach81 Even if his examples are not adequate enough or have flaws in their execution there are underlying problems stemming from Fusion. Fusion leaves a lot to be desired when compared to more mature CAD applications....

If I were trying to get a point across about T-Splines for instance I would bring up the fact that before AD bought the T-Spline functionality they were very powerful in Rhino. AD stated they were not terminating support for Rhino then they did exactly what they said they were not going to do. Anyways here we are with a broken version of T-Splines compared to what it was many years ago. Some could argue that you can just use external polygon modeling apps to do the bulk of the work and import the .obj back into Fusion and convert it to a T-Spline. The problem with this workflow is you don't have the CAD accuracy in most of those polygon modeling apps and you don't have the original CAD models to match your T-Spline work to so this makes that work flow less useful. Can it be done...sure I have shown this many times, but it is a painful at best process. I have logged thousands of hours in T-Splines and I am pretty sure my work flows are not flawed so using that as a basis of defense over missing functionality doesn't make much sense. I would be the first to defend Fusion WHEN Fusion is not at fault as I would do for any piece of software, but one thing I will not do is defend a piece of software in an area that is faulty. As I said before, @mavigogun's examples are not always the best case to illustrate deficiencies in Fusion, but to dismiss that fact that Fusion needs a lot of TLC and attention is also misguided. I wish he would keep it slightly more constructive, but we all have a right to voice our opinions.

No CAD software is perfect and only by users outlining areas that need attention and areas that are broken can any company better develop their software into something users can appreciate.

Just my 2 cents.

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

cekuhnen — Thu, 04 Oct 2018 16:37:21 GMT

@PhilProcarioJr

Actually it is just TS for Fusion that seems stagnate at the moment while for Alias it is a different story.

it seems to me for Fusion engineers and their needs are targeted while with Alias surface modelers and designers are the focus and thus get tools you need and miss in Fusion.

After all we all know designers are not the key focus for Fusion since a long time.

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

mavigogun — Thu, 04 Oct 2018 17:09:56 GMT

@cekuhnen wrote:
Mavi while I agree with some of the concerns in this thread you used two bad examples that cannot woke well because they would require trimmed surfaces which TS does not offer hence why I made the video

Claas, the video was a great example- I should have said as much (actually, it does double duty here, as it offers a bridge for the personality conflict- more on that later). It seems to me- maybe erroneously, we'll see -that there are loop arrangements that can account for these edges. A couple quick examples:

All quads, including the apparent triangle- the top Edge is actually 2 Edges. Still, I appreciate the underlaying meaning- the tool does certain things, it doesn't do other things, and not having some other imagined capacity doesn't amount to a broken tool. It may be a perfectly-bad example! 😉

@michallach81 wrote:
The point I'm making is that your designs (to an extent you've allowed us to see) reveal significant flaws in your workflow or lack of skills. You're not in a position to make demands. Topics I've replied you were blaming Fusion for your own mistakes.

Michał, you've been abundantly clear as to your opinion- it really can't be misinterpreted, given the repetition and clarity; however, unpaired with reason or demonstration, the expression hasn't been constructive.    In that previous post you reference, rather than speaking to how you saw tools were misused or misapprehended, you instead offered lengthy counter-factual rationalizions for why the required forms- features of a ship -wouldn't actually exist in the real world. It was bizarre.    This is why I cautioned against focusing on ego/personality, as these posts are working at odds to your expressed goal.

Mine isn't a unique position for someone at an intermediate level, knowing enough to question- but, perhaps, not knowing enough for consideration of the right question; this was at the heart of my lead post on this thread- "for new users, a gross misapprehension of capacity is likely."    Rightly or, it seems, wrongly, I clearly identified what I saw as problems- and suggested possible solutions. Given a choice between expressions of contempt and educating, which do you reckon would be more effective with one such as me? Take Claas as example: it sure seems y'all are fundamentally in agreement, but his tact is radically different -and far more effective.   When the perspective afforded by your experience can offer clarity, I encourage you to share that perspective.

Doubtlessly there may be occasions where I am unclear where fault lies, but the "fix what you got" thread mentioned is not one of them; nor does it serves as example of "blaming Fusion for <my> own mistakes"- at least, not from my re-reading with a self-critical eye.    Speaking to your point, Michał, I reckon it is not as unreasonable as you portray for one such as myself to characterize capacity as I have here- even if mistaken -given the very abundant presence of independently assessed failures/bugs/and the occasional tool missing a handle.    All those errors that appeared in the Timeline one day- was that the user, or an Update that broke Constraint functions in existing designs? My first reactions is "what did I do wrong?"

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

TrippyLighting — Thu, 04 Oct 2018 17:38:12 GMT

@PhilProcarioJr @michallach81 I can say that I find it increasingly difficult to respond to posts/threads like this and try to defend Fusion 360.

While @mavigogun's post show that he does not yet fully understand the principles and concepts these tools are based on, the tools in Fusion 360 are the CAD equivalent of fast food. Cheap, easy but with small nutritional value.

If you are new to the matter and come across limits, how would you know how to differentiate between your own limitations of knowledge and skills and the tools limitations ?

Many of Fusion 360's tools are incomplete and are in some state of prototype implementation:

Polygon primitive (sketch)

Box primitive,

Coil tool,

Pattern tools

etc.

These are often some of the first tools users come across before they move into T-Splines or the Patch workspace.

If a user then starts blaming limitations as the tools fault it's not a surprise, because Fusion 360 is an easy target.

Also, there are clearly weaknesses in the implementation of the T-Spline conversion tool. You can take a NURBS surface and import it into Solid Thinking Evolve. There you can export the NURBS control "mesh" as a .obj.

You can import that .obj into Fusion 360 and create a T-Spline from it and then a BRep from that. It will perfectly match that same NURBS surface imported directly into Fusion 360.

You can also convert that same NURBS surface in Fusion 360 into a T-Spline and then into a BRep but it will not mach the surface as closely or will be very "heavy", because it does NOT use the NURBS control cage, but uses another method. There is no option to switch between the 2 methods.

The method AD is using will try to create a T-Spine approximating the NURBS surface with a quad T-Spline layout.

If the surface does not lend itself to it, for example it is a trimmed NURBS surface with triangular or N-gGon layout then the converted T-Spline will try to take the shape of the un-trimed NURBS surface. I would actually not be surprised if internally the code actually un-trims the surface to do so and we still don't have an un-trim tool. Mind blowing, isn't it ?

I'd have to experiment more to see how far this can be taken and where it completely fails. I've seen an number of examples where this completely fails.

None of this can be used without proper explanation and that is where better educational materials could come in. But there Fusion 360 docs are also the equivalent of fast food with little nutritional value.

When explaining how things in Fusion 360 work under the hood we frequently refer to documents and articles written for other software and often not AD related.

I've learned more about NURBS, the whole idea behind the Patch workspace from the Autodesk Alias theory builder than I have learned from the entirety of Fusion 360 tutorials.

I've learned more about T-Splines from the 7 year old T-Splines for Rhino manual (attached) than I learned from any AD documentation.

Having said all this I find it increasingly hard to blame the user when they blame the software.

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

mavigogun — Thu, 04 Oct 2018 17:48:58 GMT

@TrippyLighting wrote:
If you are new to the matter and come across limits, how would you know how to differentiate between your own limitations of knowledge and skills and the tools limitations ?

This was the core of what I was attempting to express in the lead post; the thread title was an ill-considered hook. Thanks. Oh- and much thanks for the new document. For any following along out of interest in learning about T-Splines, NURBS, and what not, Peter previously suggested this document, too:

https://knowledge.autodesk.com/support/alias-products/getting-started/caas/CloudHelp/cloudhelp/2019/ENU/Alias-Tutorials/files/GUID-B0AAF7CA-FDBD-49FC-88BA-4F1609BC61CE-htm.html

Hey, speaking directly to the meta topic of tackling problem geometry with T-Splines, is contriving a 4-Edged pseudo-triangle, as seen in the illustration, a practical solution?

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

jeff_strater — Thu, 04 Oct 2018 17:57:43 GMT

I'm hesitant to jump into the fray here, as my Nomex suit is at the cleaners at the moment. I can't comment on everything here, but I wanted to make one point here that is illustrative of some of the dilemmas we face in Fusion development. The "convert BRep face to T-Spline" part of the Convert command. First, we realize that what everyone wants is a fully-functional conversion that would let you take an arbitrary BRep body and convert it to an editable T-Spline body. The problem is: that is not possible in the current T-Spline technology. All it can do today is to convert a single face to a T-Spline face. And, as has been pointed out, even that conversion is not always accurate - planar faces come out as a rectangle that is not trimmed. But, there are workflows where this is useful, particularly the one that is exposed in Direct Modeling in the Edit Face command (see screencast). In this workflow, it does not matter that the T-Spline face is trimmed, because that is taken care of when the replace face happens. In fact, it is better that it is not trimmed. Edit Face does not make sense as a parametric feature. But, we wanted to expose a method for a user to, in a manual, non associative way, be able to replace a face in a parametric design. Hence, we added the BRep Face to T-Spline option for Convert. But, as well noted here, this conversion is incomplete. So, the conundrum for us was: Should we withhold this possibly useful workflow from customers until the conversion can be 100% complete, or should we release it with its current warts? This is a discussion we have internally many times per week. We often come down on the side of releasing what we have. While this does open us up to charges of releasing "half-baked" functionality, we feel that addressing what workflows we can is a net benefit to our users. You are welcome to disagree.

Specific to the conversion, you could argue that it was wrong to put it under the "convert" label, since it may not be a 100% accurate conversion. That's fair. It was a UX choice to, rather than introduce a new command, to lump it in with other conversions. Which seems valid.

Re: documentation. Admittedly, this is a weak part of Fusion. But, I'm not convinced that, had we had extensive documentation about the limits of BRep->TSpline conversion, that it would get widely read.

Anyway, I don't mean to come across as defensive. I appreciate the honest (sometimes too honest) feedback.

Jeff

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

TrippyLighting — Thu, 04 Oct 2018 18:40:38 GMT

@cekuhnen wrote:

it seems to me for Fusion engineers and their needs are targeted

In its marketing and advertising, yes.

But in what other areas do you see this reflected ?

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

cekuhnen — Thu, 04 Oct 2018 18:41:15 GMT

@mavigogun

Fun fact I suggested this to @TrippyLighting because the Alias document is one of the best

Rhino is also good Alias is better

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

TrippyLighting — Thu, 04 Oct 2018 18:52:07 GMT

What happened to @jeff_strater's post ?

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

cekuhnen — Thu, 04 Oct 2018 19:06:06 GMT

@TrippyLighting

Yeah it is gone - it was actually a good insight and explanation!

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

TrippyLighting — Thu, 04 Oct 2018 19:09:00 GMT

@cekuhnen wrote:

@TrippyLighting

it was actually a good insight and explanation!

Yes, and very much appreciated!

Ive seen this several times though where I receive a notification to a thread update and when I go to see the post in the thread there is none!

I am wondering whether I've offended with my overly dramatic fast-food comparison or if the forum software is at fault (or both).

Re: Example of Basic Tool Disfunction: Primatives, BRep to TSpline Conversion

mavigogun — Thu, 04 Oct 2018 19:21:55 GMT

@TrippyLighting wrote:
What happened to @jeff_strater's post ?

Don't fret- I took a screen capture: