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Facets on curves

SOLVED
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Facets on curves

Hi. Hopefully this is an easy one to answer..

Whenever I pull a tube or curve, or blend a corner greater than 20mm, the curve is not one smooth surface - instead it's shown as multiple flat surfaces. Anyone know why, and how I stop Creo from doing this? I need one prefect smooth surface.

On small blends (<5mm) it's smooth, but not sure if this is just because of the scale.

I 3D printed a previous piece thinking it would be smooth even though it had facets on screen, but the model did indeed come back with facets as shown on screen.

Any help would be great

Thanks

Rajesh

1 ACCEPTED SOLUTION

Accepted Solutions

Re: Facets on curves

Graphics quality settings...

You can have better display of graphics but it will have some CPU cycle overhead. I use these settings when I want to do screen images:

Model_display_quality_settings.PNG

Green means do not turn on.

Entity_display_quality_settings.PNG

BUT: WARNING! If you use these setting, change your config.pro to include the following setting:

Save_model_warning.PNG

Reason being that saving the part or assembly will also save a LOD version of the facet model by default. If you are not using JT files, change this setting by default to keep your saved and version files at a reasonable size. I am not sure how PTC actually uses the LOD data, but it is a huge overhead if you don't need it. It doesn't seem to affect previews. LOD means "Levels of Detail" and is a holdover from the old virtual world days.

14 REPLIES 14

Re: Facets on curves

You can control the smoothness of the STL file with the STL dialog. Interesting that you noted similar characteristics between what is on the screen vs what printed. This really should not be the case. If you re-import the STL file, you will see what was exported.

Here is an exaple:

STL_dialog.PNGDefault settings

The import on the left is default. The right was exported using .01, .05, .1

STL_result.PNG

I have my default graphics quality settings fairly low.

As for the on-screen graphcis quality, there are several settings. I know just how annoying it is to not be able to see intersects or other accurate representations on the screen. I will add some info in the next post.

Re: Facets on curves

The model is probably smooth, but you resolution is not. There can be performance issues when setting your resolution really high.

For you 3D printing, are you exporting an .stl file? If so, you can adjust the Chord Height and the Angle Control down to get a better triangulation, but remember this is still triangulation. The smaller these numbers, the smaller the triangle used to make the part, the larger the .stl file size will be.

I, myself, have done a lot of 3D printing and attest to the number/size of triangle will make the part smoother and smoother. It will just take a lot more processing time to get there.

Thanks, Dale

Re: Facets on curves

You must have faster typing fingers today.

Re: Facets on curves

Graphics quality settings...

You can have better display of graphics but it will have some CPU cycle overhead. I use these settings when I want to do screen images:

Model_display_quality_settings.PNG

Green means do not turn on.

Entity_display_quality_settings.PNG

BUT: WARNING! If you use these setting, change your config.pro to include the following setting:

Save_model_warning.PNG

Reason being that saving the part or assembly will also save a LOD version of the facet model by default. If you are not using JT files, change this setting by default to keep your saved and version files at a reasonable size. I am not sure how PTC actually uses the LOD data, but it is a huge overhead if you don't need it. It doesn't seem to affect previews. LOD means "Levels of Detail" and is a holdover from the old virtual world days.

Re: Facets on curves

I can see a useful tool for the dialog to help users determine an appropriate setting as in Course/Medium/Fine along with the fine tuning settings already available. The defaults really are very course.

I did confirm that changing graphics quality to very high did not alter the default export settings.

Re: Facets on curves

Hi all

Thanks for the responses.

Clearly I have stumbled at the first hurdle >> where do I find the dialouge box where I adjust those settings? I am using Creo Elements / Direct Modelling Express - can't even find the version number but a downloaded it from PTC within the last couple of months.

In my FIle menu, I have options for Settings, Options, and Customize, but cannot find the options you've suggested above.

Thanks..

Re: Facets on curves

The options in Direct Modeling Express is simpler but should be just as effective.

You access the option when creating the export file:

STL_in_Express.PNG

Re: Facets on curves

Antonius - Thanks; I thought that was it.

What values should I put in each box for a smooth surface? Is it 0.5 and 0.1? I really don't mind going lower - I'd rather have a bigger file which may cause niggles sending to others, rather than a model that again comes back with facets. By way of example, the widest curve I have pulled is around 50mm diameter.

Plus in the above chain, there's mention of adjusting graphics settings for better on-screen viewing. Can I make these changes in DME?

Finally, how do I open an STL in DME? Or do I need to find a standalone STL viewer? Any recommendations? I want to view the final STL on my screen to confirm smoothness before I send it away for machining.

Thanks!..

Re: Facets on curves

In regular Pro/Creo you can hit apply before save. That gives you a preview. Is there a way for you to do that?

Also, on the chord length, I got to a point where it would let me put in a smaller value than what it returned. Not sure why the limit.