Converting designs made in Zbrush to Fusion solids

[sertanV7D8A]

Hi everyone,

I am working with a designer and he works with solid works, but the design I gave him has a very organic look. Therefore he sculpted it in Zbrush. The model will go into production therefore we need a stp file. He then tried to export it to Stp and the result looks polymeshed and low quality.

He seems not to be experienced how to maintain the smooth design from Zbrush to solidworks, or in my case Fusion360. I am attaching the file he sent me. 

I would greatly appreciate if you could tell me what steps to follow, so we can continue working with zbrush to scuplt our organic shapes.

This item is supposed to be a half shell with 2mm wall thickness. Looking forward to your answers! I am attaching the STP file if you like to try it out. 

[TrippyLighting]

The designer should export that poly mesh from Z-Brush as a quad mesh in .obj format. This can then be turend into a T-Spline in Fusion 360.

In general, this design is very simple. The base shape can be designed in Fusion 360 is a few minutes using a T-Spine or even solid model lofting. Add 30 minutes for the little bumps or divots.

[Anonymous]

BTW. For rendering purposes... I noticed that Fusion 360 renders triangulated bodies much-much better if they are converted to Mesh (in comparison to Solid or Patch bodies). The net on meshed bodies is almost not noticeable.

Here is render of the same body represented as Mesh and Solid (it does not matter which was converted from which).

[TrippyLighting]

The reason for that has really nothing to do wth the render engine.

A mesh is assumed to be a smooth body and the mesh is just an approximation of that smooth body. As such a interpolated lightning algorithm is used. the finer the mesh the better that works.

If a mesh is converted into BRep  either within Fusion 360 or by saving it in a .stp file as a surface or solid model, then the term BRep already explains what is being done - boundary representation - the mesh is interpreted to be the end result, and no smoothing is applied.

In genreal, however, the LOD (level of detail ) algorithm in Fusion 360's render engine sometimes also causes the render results to show clear faceting and thus undesirable results. Here the ability for he user to control that effect is needed. In a Sub-D modeler you can simply increase the level of subdivision.

[sertanV7D8A]

Could you tell me the steps in more detail?

So he designed this star in Zbrush and then he saves it as obj. Then what do I do?

I know your suggestion of using t-spine bodies is fast and cool. However, I experience so much trouble with working t-spine bodies in modeling mode. I just want this file to be delivered to me as sculpted and I can have it in fusion and export it as stp.

Please let me know what steps I need to take. 

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@TrippyLighting wrote:

The designer should export that poly mesh from Z-Brush as a quad mesh in .obj format. This can then be turend into a T-Spline in Fusion 360.

In general, this design is very simple. The base shape can be designed in Fusion 360 is a few minutes using a T-Spine or even solid model lofting. Add 30 minutes for the little bumps or divots.

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[sertanV7D8A]

Hi Guys,

I appreciate you trying to help, but I got more confused than being helped. Could you just tell me in a simple way which steps to follow?

So my designer will sculpt it in Zbrush and what steps to follow to make it manufacturing ready file? He doesn't have fusion, but solidworks . So either I will convert the file he sends me, or I will suggest him what to do.

Let me know if you have a suggestion

best

[mcramblet]

Is it possible to post or send me the ZBrush file? I can show you the method that I use, both in ZBrush and in Fusion. It might make more sense to show this with the actual file being used as the example. As always, the tricky thing is going to be balancing the level of detail of the ZBrush model with a CAD file that is still workable (e.i., not too dense with surface control points), for production purposes.

[PhilProcarioJr]

@sertanV7D8A

In Zbrush make sure you run the mesh through remesher and make sure your polygon count is below 20,000 faces. This will produce a quad mesh that will translate well in Fusion.

Then save the model out as an .obj file.

In Fusion make sure triangulate mesh is turned off in preferences.

From the menu click import mesh and import your .obj file.

Now switch to Sculpt and right-click on your mesh and convert it into a T-Spline.

Check your T-Spline to make sure the body looks correct smoothed.

Now right-Click on the T-Spline body and convert it to a B-Rep.

Now you have your solid CAD model.

[mcramblet]

@sertanV7D8A-

By the way, one tip I would mention for this process is to build the ZBrush files with multiple ZB "tools". For example, with the star fish design, if the overall star fish shape was one tool in ZB and the bumps detail was created as a separate tool. I've found that when a ZB model is created using separate, individual tools or bodies for the detail, the results are better. The various parts can be brought into, then converted in Fusion and combined with more success, as opposed to having one body that contains all of the detail.

[mcramblet · Accepted solution]

@sertanV7D8A-

These types of shapes can be done within Fusion, with a little work. I've actually done similar types of shapes for a production job, all within the CAD environment.

Jobs done completely in CAD, will have fewer issues than trying to convert files to use in CAD. Of course, if the level of detail needed is really high, other methods might need to be pursued.

[sertanV7D8A]

I am definitely into using Fusion and not mixing Zbrush etc. I am just new at t spline bodies and sculpting them. For example, I prefer to sculpt this star myself. I have tried but failed. Is there a quick way to create a tspline star with internal symmetries? 

[mcramblet]

@sertanV7D8A-

Here is a link to the basic Starfish:

http://a360.co/2mwVKvq

You can download this and open it in Fusion, to get a better idea of how it's put together. It does have radial symmetry.

[mcramblet]

@sertanV7D8A-

I've also placed the starting shape in the file. This simple 2D set of surface faces is the starting point for the final starfish shape, just extruding faces, then adjusting to what I needed:

With this, you should be able to make the starfish that you posted at the beginning of this thread.

[sertanV7D8A]

Thank you so much for all of these. I just downloaded the file, but it doesn't have the history. I have downloaded as fusion 360 file but it doesn't display any history. Would you mind attaching the file to your message instead? 

Thanks a lot

Sertan

[mcramblet]

The sculpt environment doesn't keep a history of all of the various manipulations, like it does in the modeling environment. That would actually be a huge amount of history to keep track of and it wouldn't be practical. Instead, the sculpt bodies always remain editable, and when you exit the environment, the resulting body updates in the history. So there isn't a history that you can play through to see all of the steps that were used to go from the starting point to the end point.

[sertanV7D8A]

Then could you tell me how you started that 2D shape? Because I can't seem to figure out how to convert sketches into T-splines. 

If you can tell me how you got to that 2D t-spline, it will be very helpful.

thanks

[TrippyLighting]

One does not usually start with sketches in T-Spline mode, at lest not for thee rather no-technical objects.

However, you can create a sketch and use the match command to attempt for the T-Spline to match the sketch shape. However, in order to do so the sketch and the T-Spline should already be close in shape to each other.

[mcramblet]

@sertanV7D8A-

Below is a screencast showing the basic idea of how the 2D faces were made. It's not the smoothest, but it's getting late. When I'm creating shapes that will be thermoformed cavities, I always start the sculpt forms this way. Basically, trying to logically layout the faces for the general shape. The "Sketch" in this case was done elsewhere and brought in as a canvas, just for reference. Hopefully this will get you started.

[mcramblet]

@sertanV7D8A-

One other resource that may be of use to you is the old manual for the T-Splines plug-in for Rhino. It's about 6 years old and it obviously pertains specifically to T-Splines within Rhino, but the general information about the different methods/ways of starting a T-Spline object is still valid and is helpful in understanding things. I don't believe I've seen documentation this thorough for the Sculpt environment of Fusion 360, but I think it would be worthwhile for Autodesk to update this information as a resource. If there is something like this for the Sculpt Environment, maybe someone can chime in.

Again, this isn't 100% transferable to Fusion 360, but it still has good information:

http://www.tsplines.com/support/usermanual.html

[sertanV7D8A]

Thank you so very much for everything. After your last screen cast I finished my design. Actually, this has been so helpful that I managed to finish the whole project.

It is a learning process. However, I wish Autodesk made things more intuitive, and obvious. I mean the first thing that came to my mind that I should be able to make a sketch and convert it to a t-spline then start sculpting it. Trying to sculpt without having a profile to start with makes it very difficult especially in more precise designs.

Additionally, they should provide texturing tools that can cover a face with certain bumps, etc.