topic Re: Photo Render Projection in Visualization

Photo Render Projection

Anonymous — Thu, 11 May 2023 10:28:13 GMT

Hi,
i render a model with background picture. But after rendering the model is hanging within the background picture. How to align it?
I am using Archicad 10.
Thanks
Paul S

Re: Photo Render Projection

Dwight — Sun, 14 Jan 2007 04:09:07 GMT

I am hanging loose myself.

Post your rendering and i will give you some hints.

It helps to make your camera viewpoint approximately that of the site photo, then you "walk" the camera into the exact place with the navigation tools in an OpenGL rendering before making the real photorendering.

You have heard of the Align View tool. Forget it! That tool isn't very good unless you know the precise heights of adjacent points that help the routine do its magic stuff. Even then it is not very accurate without the secret trick of zooming in for exact pixel accuracy.

Re: Photo Render Projection

Anonymous — Wed, 17 Jan 2007 16:05:17 GMT

what did you use to do the free-form structure?

Re: Photo Render Projection

Dwight — Wed, 17 Jan 2007 16:07:11 GMT

That's an oblique view. A perspective view is required to use the background.

Re: Photo Render Projection

Anonymous — Sat, 27 Jan 2007 05:48:53 GMT

Hi Dwight,

[It helps to make your camera viewpoint approximately that of the site photo, then you "walk" the camera into the exact place with the navigation tools in an OpenGL]

Would you please tell us more of this trick?, I myself been frustrated many times by the 'Align View' tecnique.

Mbarouk

Re: Photo Render Projection

Dwight — Sat, 27 Jan 2007 06:23:25 GMT

The fellow who took on the design of the Align View tool had his hands full:
- a competing product had this feature. So Archicad needed it even tho sites rarely provide the geometric accuracy to place orienting nodes - certainly interiors are easier.
- photographs are distorted, meaning that aligning perfectly with archicad's perfect world CANNOT HAPPEN in a photo.
- few users will understand to zoom in to the exact pixel level when placing the orienting nodes for absolute accuracy because nobody except me (Illustration in Archicad) warned them about that.
BTW: As frustrating as it is, the Align Tool DOES WORK. The proof of this is inserting a piece of furniture into an Archicad rendered image. This approach eliminates analaog irregularities and proves tool operation.

This is a delicate subject for me because since we have the live OpenGL with photo background capability, it was always faster when using photos where the viewpoint was known to enter the camera coordinates and use navigation tools to "walk" the camera. How hard can this be to understand? Once you know the picture target (by criss-crossing the image to find its center) make the camera target that spot. Drift the camera view left and right, up and down, and experiment with camera view angles unless you know that from the EXIF data in the image file.

Perhaps you are offended because this looks like "fudging." It is. I regularly get files from people who ask me to align their camera view to a photo. In those cases, however, the photo has the survey building volume described by site sticks, so making a roof peak line up between two sticks at the ridge height is fairly easy to do navigating in OpenGL by trial and error.

This brings me back to the main point - neither system works without clean visual references within the background image.

Re: Photo Render Projection

Anonymous — Sat, 27 Jan 2007 08:37:08 GMT

Hi,

Thanks, that was quick.

Will experiment, thank you again

Mbarouk

Re: Photo Render Projection

Anonymous — Sat, 03 Feb 2007 16:52:40 GMT

Hi Dwight,
thanks for your hints. With camera view point, i got it with background picture.