Revit Cylinders = zillions of 3DS MAX polys...ouch!

[mrcamper]

Help.

I am exporting my Revit model to ACAD then to MAX. I have a model of a public building with a large amount of railings and light standards in the design. Everything works, but...... All of the rounded elements when exported to ACAD2000 then converted to 3DS MAX ver. 6 becomes an unbelievable number of polys. I then tried ACAD2000 to ver. 5 MAX and its even worse. I have tried several check box variations on the DWG export dialog, but get similar results with whichever variables are checked.

I started by following the instructions in the .pdf, "Using Revit with VIZ," Is there some secret way of getting the polys of rounded objects to not become a disordered polygonal mess?

Maybe a later version of ACAD200x maybe help?? Any obscure MAX settings or such? Or perhaps taking my Revit install disks out into the parking lot and sacrificing them to the 3D gods?? Going back to DataCAD. hahahaha, just kidding!

For example: The final resulting 3d model of the standard Revit commercial floor toilet soared to over 2,500 polys each. urk.

...and yes there is a specific reason I have to get the model into 3DS MAX.


Thanks in advance.

moving to general....Z

[mrcamper]

Post got moved .... kewl!


Here is a screen shot of the problem.....

[Steve_Stafford]

I can't help you and I think you are breathing rarified air on this one. I can't think of a guru on this forum who has attempted this transition, if they have they haven't talked about it here yet. You might want to run this by the support folks at Revit (866-GO-REVIT) and see what ideas they have.

[Scott D Davis]

The problem comes from the translation: the export forms only 3D faces, not solids. A curved or round surface must be interpreted as a bunch of 3D faces.

You can make the railings in Revit octagonal, and then when you export, you will get one 3D face for each side, instead of dozens of facets for each area. Treat anything in your Revit model that is curved as a multi-segmented line, rather than a true circle or arc. Yes, its not going to render perfectly, but it'll be faster than all the polygons.

[hand471037]

I'm having simular issues with exporting fro Revit to Radiance; the issue is that Revit models become polyface meshes & 3D faces in AutoCAD, which upon export are triangulated, thus leading to the millions of polys. Have you tried exporting the file as a DXF from Revit, and then opening it in MAX directly? What happens when you leave AutoCAD out all together (even though you're probably opening the file in AutoCAD to clean up layers and such prior to 3DS export for material mapping)?

[mrcamper]

Wow, thanks for the mega quick responses!!

"....rarified air" - Yipes, I do have a lage environment created, but I see lots of people exporting their stuff, I guess I may be the only person using circles extruded as railings. -erk!


"......try exporting the file as DXF...." - that will be the next thing I try.


"....make the railings octogons..." - that will be what I do Monday if the DXF thing doesn't work.


Thanks guys!

[Arnel Aguel]

Richard Mcarthy had a similar issue with railings after linking his file to max.
Railings in revit is a poly hungry crazed or in general all curve surfaces in revit. If you try to observe, all curve surfaces in revit are automatically drawn as smooth curve with a very fine subdivision of curve segments to achieve this. In ADT this is not the case the default is a segmented curve but you can control the smoothness thru the "aecdevfacet" command putting a small value will you give a smooth curve.

If you are using file linking (pdf whitepaper) as what you said, there are two ways of reducing poly count.

1) Under file linking manager dialog box goto the advanced tab panel and open exclude object by layer then pick the layers that you are not using to exclude this in the file linking translation.

or second is to reduce the segments of smooth curve in revit file by adjusting in max.

2) Under file linking manager dialog box goto the basic tab panel then under ACIS Surface Deviation change the default value of 1 to a higher number.

The way i look at your image the additional faces is not along the curvature of the railing but along the height and this might be difficult to control in 2) above.

Or you can try first excluding the railing layer in 1) above then check the poly count of your scene under summary info and compare with the railing included.

[mrcamper]

ok, redrew the whole railing shabang, all the toilets, etc,, everything curved. Extruded railings with 16 sided polygons instead of circles.

Export has gone from 3.2 million polys to less than 500k polys. puh!

Lesson learned: no curved surfaces if planning on exporting to MAX.


-sigh- ......the beat goes on.

[shaunv68276]

in acad set 'isolines' and 'facetres' up before exporting to max/3ds. this eleminates the amount of surfaces. typical Isolines = 8/12 , facetres = 10. sorted :lol:

[Martin P]

this must be a similar problem, i have cylindrical columns in revit that when I export 2D to Autocad it creates millions of little bits.. Its a real pain because the drawing is really clunky in autocad for no reason other than this so I have to redraw them 2d in autocad before I send it to anyone - its a bug.......

[mrcamper]

in acad set 'isolines' and 'facetres' up before exporting to max/3ds. this eleminates the amount of surfaces. typical Isolines = 8/12 , facetres = 10. sorted :lol:

Yep, did that and got this......(see image)

It changed the way the cylinders were presented to the screen, but had NO influence on the geometry output either to 3ds, dwg or dxf once imported to MAX.

Note: Autodesk, $ux04$.................(with 17 years of experience with Automess products I could go into a major flame here, but I won't. )

[hand471037]

If I remeber correctly, AutoDesk hasn't really changed it 3DS export feature for the last few years. Unless it's different in 2004 (and it doesn't look like there is a whole lot that is different in 2004!) than it's the same tool we were using with R14. Which is a shame, for it's not a very good export tool.

[shaunv68276]

Ok, do an Optimize Modifier in Max/Viz to get rid of the extra vertices. I have tested this and it does work. :oops:

[Martin P]

[quote:42780a29c9="Shaun van Rooyen"]in acad set 'isolines' and 'facetres' up before exporting to max/3ds. this eleminates the amount of surfaces. typical Isolines = 8/12 , facetres = 10. sorted :lol:

Yep, did that and got this......(see image)

It changed the way the cylinders were presented to the screen, but had NO influence on the geometry output either to 3ds, dwg or dxf once imported to MAX.

Note: Autodesk, $ux04$.................(with 17 years of experience with Automess products I could go into a major flame here, but I won't. )[/quote:42780a29c9]


2D export to dwg with cylinders create circles formed from hundreds of polylines, it is a revit exporting bug, I think, I doubt there is much you can do in either Autocad or 3Ds or whatver to fix it??

[narlee]

Twist on the subject:

When I bullnose shelving and look at it in 3D, the 3/4" thick bullnose looks strange. Upon investigation, I discovered that the number of arc segments produced by my half-circle-shaped sweep was just a few. I improved the look by making the bullnose out of 2 quarter-round, thus doubling the number of arc segments, if you will. AutoCAD has a Display Resolution under Tools>Options>DisplayDialogueBox where you can globally adjust "Arc and Circle Smoothness." I'm wondering if anyone has seen anything like it in Revit, because, for me, the curves are generally on the skimpy side of this equation.

[hand471037]

That 'arc and circle' smoothness doesn't effect the model, only the representation of it visually. I don't think Revit lets you control this, for it's altered automatically depending on scale of the view, IIRC.

[Richard McCarthy]

Hey mrcamper!

Looks like you are in the same boat as I did last year.. having tried all kinds of stuff to get the poly down. In the end I did what you did as well, remade the ALL the rails.


The model I had was only less than 80,000 polygon and it's a DOME SHAPE too, but when I first exported and imported into MAX with DWG file link, it was 1 million polygons! It's only after some investigation I found the culprit is the bloody STAIR RAILS which cost roughly 900,000 polygons all together!! Jesus, Revit definitely needs an option for this.. One stair (with 2 rails on each side) can have quarter of a million (250,000+) polygons !!!

So, the moral of the story is, don't use STAIRS! USE lifts!! haha, nah just kidding. Moral of the story is to use rectagle cross section for rail extrusion. (if you have a MASSIVE MODEL)

Another thing you could try is to use the polygon reduction tools in MAX (I think it's called "optimise", or you could try other solution from other vendors.. or export to Rhino for poly reduction, but the result is usually worse and messy then manual optimisation eg. Draw your own cross section and extrude)

[Richard McCarthy]

This is the proposed BMW showroom (pardon the blatant likeness to the Norman Foster building in Germany, I swear I have absolutely NO IDEA at the time of design my building look so similar ....)


http://www.cgarchitect.com/vb/showthread.php?t=2204&highlight=BMW