I’m trying to drape an aerial photo onto a 0.25m grid.
The photo that is being draped looks like this:
When I try to use dcdrape to drape the photo it ends up looking like this:
Any help on how to make the rendering look more like the photo with a higher resolution would be greatly appreciated.
Hi,
The size of the texture created and used by DCDrape is limited to about 1600 per 1600 pixels. So if your aerial photo is greater than 1600 per 1600 pixels it will be down sampled before being draped.
Bentley Descartes SELECTSeries 3 will be offering a new draping technology which has no such texture size limit.
Here is a video about the raster draping technology : communities.bentley.com/.../189367.aspx.
There is also a Technology Preview program for Bentley Descartes SELECTSeries 3 that you could join if you want to test this new raster draping technology (see communities.bentley.com/.../187504.aspx for more information).
Thanks,
Mathieu
Unknown said: The size of the texture created and used by DCDrape is limited to about 1600 per 1600 pixels. So if your aerial photo is greater than 1600 per 1600 pixels it will be down sampled before being draped.
Mathieu,
Is the entire image downsampled, or is it first clipped to a bounding rectangle around the surface geometry on which it is to be draped? That is, would I get better results if I clipped my images as close to the surface limits as possible, versus having a lot of "overhang"?
Thanks.
Hi Morten,
Yes you are right.
I should have mentioned that all the images attached in Raster Manager and turned on for draping with DCDrape are going to be merge together into a single, limited size texture. So clipping a big images into smaller tiles and having all those smaller images setup to be texture at the same time will result in the same quality as using the original, bigger image.
But if you want to texture a particular location and you just have a big image covering more than the region of interestest creating a small image for the region of interest and using this image instead of the big one will result in quality improvement.
Nothing has been changed or is going to change in SELECTSeries 3 for DCDrape. If you want to drape huge raster you will need to switch to the Scalable Terrain Element that will be available in Bentley Descartes SELECTSeries 3 (see for more information communities.bentley.com/.../187504.aspx).
Hi Matheiu
Thank you for the clarifications.
I'm a Descarte Beta tester and have high hopes to the Scalable Terrain Element - but in the currect Beta version there are some significant errors in the draping, so the renderings are not very good.
There is a TR on this. So I hope it is corrected in the next beta.
Kind regards
Morten
If you are talking about the animation the TR is already fixed. I'm planning to recreate the animation with a fixed Bentley Descartes and post it on the related thread.
Hi Mathieu
Where can I get the fixed Descarte Beta?
The fix is not yet available for member of the Bentley Descartes SELECTSeries 3 Technology Preview community.
Hopefully it will be before the end of the year.
But the quality problem should be solved by deactivating the progressive display, which can be done by setting the configuration variable STM_PROGRESSIVE_DISPLAY_ACTIVATION to 0.
Note that for some dataset like Louis' dataset turning off the progressive display don't solve all problems.
Hi there,
I'did tested the image draping some time ago without issues with a mega orto photo that had 1Gb+ size and thousands of pixels in size. 10cm res.. It was in .ecw format, that as seems to progresively load-unload data as it is needed, so I've a whole city raster loaded in a blink of an eye without performance lost, and it did work whell when dc draped.
Hpe it helps.
Hi Kepler
The problem only occurs when I render a picture or movie..
I have produced a movie that I will upload later.
Hi Kepler,
I think you are confusing an image displayed by Raster Manager and an image draped on dgn element representing a terrain by DCDrape (i.e. : DCDrape.pal).
Raster Manager can handle extremely huge raster without problem. But DCDrape can only handle a texture of about 1600 per 1600 pixels (note in a Luxology view the texture is a bit greater, but still limited).
Sure you can do 3D rendering and animation with a flat image. But if you want to texture a terrain with an real aerial photograph you need to use DCDrape, or use the new technology developed in Bentley Descartes SELECTSeries 3.
No no, I'm aware of what dc drape is about.>>> imprint an image over a 3d model, ussually a terrain. But probably I did not explain myself correctly, what I meant is that I tried to drape a huge image on a mesh and saw no issues. And the singularity was its format, and just commented its behaviour on screen in realtime. But if you know of and internal limitation I might be wrong, but as converting the source image to .ecw is just a matter of few clicks it might worth a try.
Are you sure that your image was actually draped and what you were seeing was just the flat image?
You said "that as seems to progressively load-unload data". That kind of behavior is only available when an image is displayed by Raster Manager.
Note that, to be draped, the Draping toggle of an image must be turned on (see communities.bentley.com/.../bentley-descartes-image-draping.aspx for more information).
Below is three screenshot showing you the result of displaying an ECW raster file with Raster Manager, compared to draping the same ECW raster file with DCDrape and using the draping technology developped for STM.
Note that the ECW raster file used is quite small (about 13 Mb, 14250 by 12263 pixels) and the quality degration when using DCDrape is already quite obvious.
ECW Displayed By Raster Manager
ECW Draped By DCDrape
ECW Draped for STM