Work-Around For Resonably Smooth Curved Objects

[studioCJF]

Here is another work-around for the faceted arcs/curves issue...

Because an extruded circle maintains its shape (IE: no facets) it is possible to carve away at the solid and maintain a smoother shape as follows:

1) create a solid extruded cylinder at the radius of the extreme outside surface of objects profile
2) create a void revolve or sweep with negative of the profile you are trying to replicate
3) the solid cylinder should automatically be carved by the void revolve/sweep (if not use "Cut Geometry" tool)
4) Cross you fingers and hope you don't get the dreaded "can't keep elements joined" message
5) if #4 comes true adjust the profile sightly (trial & error) until solid object is cut

Other observations:
*as you can see these objects are fairly small (45mm or 1 3/4") for the main cylinder so small detail is achievable
* remember you can cut an object multiple times... so if one of the cuts cause #4 message then use the "do not cut" tool to uncut the solid object then try using the "cut object" tool and your various profile in a different order... sometimes it make a difference as to which cut profile is used first
* the larger the object the smoother the curve small objects can be very hard to achieve
*rant... This has been asked many times i wish we could just get a user preference similar to acad that allows you to set arc/circle smoothness

Take a look at the attached Generic Family attached and see two versions of the same object the top one is made by using a Solid Revolve and the bottom one is made using the steps listed above. the top one is definitely faster and easier to make but looks choppy. Bottom one takes more time and a little more brain power to think in the negative but looks much better

Have fun whittling

studioCJF

[Elmo]

Interesting solution. How does the family handle afterwards? Is light still or does it feel sluggish when added to other families or projects?

[studioCJF]

Elmo

I have not noticed any change in how the family functions... Although I cannot confirm the change in file size I am resonable sure the change was minimal in the families that I manipulated this way. Also since my initial post i've noticed the results can very depending on what you are trying to accomplish, as you can see in the example, if you look closely in the area that was cut with the revolve you will still notice some faceting but the overall objet is still much smoother than if it was created as a revolve. so one must decide for themselves if it is worth the extra step to create the smoother shape

The main reason that I went throught the extra step is that I found that the shape is not automatically rendered as a smooth arc/circle when rendered as I expected it would be based on other posts regarding this topic. Again IMHO it greatly depends on the scale of the object being created

[CampbellArch]

studioCJF, I have tried your work around but am still encountering the same faceted effects. My problem starts with your first premise, "extruded circle maintains its shape with no facets". I am extruding a roughly 7" diameter circle and it appears very faceted. I have two smaller curves which do not appear to be faceted. I don't get the difference. I built the object both ways, the current which is with a revolve and the second using your method and I ended up with similar results, still faceted curves. I've attached my family in the event that you are able to see something I am not seeing.

[aaronrumple]

Elmo
The main reason that I went throught the extra step is that I found that the shape is not automatically rendered as a smooth arc/circle when rendered as I expected it would be based on other posts regarding this topic. Again IMHO it greatly depends on the scale of the object being created

This is why I use DWG/ACIS solid for export to 3DS Max. (I know your probably just rendering in Revit.) Using ACIS, i get a true massing in DWG format and can chose the resolution of the faceting I want on the 3DS import. It typically import in two batches. The first will be the architecture with a low resolution setting - between 1/8" and 1/16" surface deviation. Then I'll import detailed items like furniture with a resolution of .001"

Unfortunatly FBX doesn't let you set the accuracy for curves. So I only use that for the objects that don't export to ACIS well. (Ceilings with lots of holes and cuts don't translate from DWG to 3DS well.)

I also use a lot of model lines in light fixtures and such. Then on import into 3DS, I'll set the radius I want for rendered splines. Again I may have to do the import in a couple of passes, but it keeps the 3DS model light and detailed.

I know that doesn't help Revit rendering - but if you do use 3DS, it gives you some options on overcomming some of the default settings of Revit.

[CampbellArch]

Aaron,

Any thoughts on the post or family I just presented. I do not see the results noticed in StudioCJF's images. I used the method he prescribed, but it does not appear to work. Any ideas?

[aaronrumple]

Aaron,

Any thoughts on the post or family I just presented. I do not see the results noticed in StudioCJF's images. I used the method he prescribed, but it does not appear to work. Any ideas?

There is just little control inside Revit. It has its own rules for faceting. So you just have to go with what it gives you. I've just stopped fighting it.

[CampbellArch]

What about printing to 3D Printers such as Z Corp's. I need to print a 3D prototype of this object on a Z Corp 3D printer and I am concerned that the physical model will also be faceted. Do I need to export this object to AutoCAD before I print it to Z Corp printer?

[aaronrumple]

If I'm correct a ZCorp 3D plotter wants an STL ro ACIS file. So your're going to be exporting 3D geometry anyway. In this case the export should be fine.

(...and what scale are you plotting? Will your output even show such fine detail?)

[studioCJF]

Alex

See the attached files... there are 2 versions with CJF in the title...

The 1st one (*CJF1.rfa) was done by deleting your original "Revolve" or the round cap shape (I copied the profile to the clip board first) then I created a round/cylindrical "Extrusion" for the cap. I then created a negative "Void Revolve" of the profile that I copied to the clipboard and used that to cut the cylindrical extrusion you will notice that the shape is still somewhat faceted but it is smoother. The facets are caused by the "Revolve" and you will notice them more prominently on the underside where it is cutting more of the original cylinder

The 2nd one (*CJF2.rfa) was again done by deleting your original "Revolve" and creating cylindrical extrusion for the cap.
I then created a negative "Void Revolve" of the top half of your original profile without the underside portion of the profile. The remaining underside profile was cut out using a separate "Void Extrusion" using the diameter dimension from the original profile. You will notice that the shape is sightly less faceted from the 1st attempt. That is because an "Extruded" cylinder retains its shape better than a "Revolve". The more you can do without using a "Revolve or "Sweep" on a circular object the smoother it will be, but sometimes there is no way around it.

Before I created the "Cutting Shapes" I copied the 2 stud-like objects and the gasket object off to the side and brought them back into place after the cuts were made otherwise the new "Cutting Shapes" would have cut them as well and cause them to disappear. After that I (as I usually do) I "Joined Geometry" of all the objects that are the same material... in this case all the orange objects. By joining objects sometimes you will realize even more smoothing of the objects but in your object this was not the case. The best way to see what i mean her is to join a cylindrical "Extrusion" to a chamfered "Blend" (BTW cylindrical blends also facet) that is attached to one end of the cylinder you will see that the "Blend" object will attach and smooth to the round cylinder at the attached edge.

As I've said before... this procedure is not the fastest and takes some thought (IE: applying a negative cut shape to a round/cylindrical solid -vs- creating the solid object from a "Revolve/Sweep/Blend"

I decided to add a screen shot with your original in the lower right corner and 2 views *CJF2.rfa on the left

Hope this helps and by all means feel free to use the new family...


Edit: Alex i just noticed that the black gasket on the botton was made from a "Revolve" you could remake that object using a dounut shaped cylindrical "Extrusion" if you wish...