Render time

[redstamp]

Have posted on this subject before in Yahoo forums, and got couple of good replies. Just wondered if anyone could improve on those suggestions, as they are not working perfectly...

I am using a dual core processor and want to speed up the render time of my images.

Current version of TG (not 2) doesn't support dual core, so I am trying to split the image into 2 parts, render each in a different Terragen instance - therefore using both cores to the max - and then stitch back together in Photoshop.

If I am rendering a 3000x2000 final image view, I change the camera pitch to say 15 degrees either side of the desired view and then render two images of 3000x1000 (with a small overlap to ensure correct alignment).

Everything looks fine until I come to stitch the images together and they don't line up properly 

It looks as if one image is being taken with a slightly different camera zoom setting. I can only assume that changing the pitch is altering the camera zoom as well - although (and after plenty of maths) I have checked and when changing the camera pitch, TG changes the target coordinates to retain the distance between the camera and the target at the new pitch.

I have considered rendering two images with only changing the camera bank by 180 degrees, but this will produce an overlap of 33% and therefore probably not reduce the render time significantly.

Any other suggestions?

Cheers,
Jon.

[Kranky]

To render a TG 0.9 image in multiple parts, you decrease the render buffer to about 2MB (you find it in the render settings, where you can set up the atmosphere quality, in the last tab). Then TG will render very small parts - and small stripes.

You open two instances of TG and you load your scene in both instances. In the first you can click on the render button. The rendering will start from the top of the window (from the sky).
In the second you have to turn the camera upside down - you don't change the pitch - you have to insert 180 into the banking field. Then you can start rendering in the second instance too. This rendering will start from the top also, but you turned the camera 180 degrees - the ground will be at the top.

When you can see that the two renderings are overlapping, then you stop both and click on the save-buttons. After that you have to turn the second image back in photoshop (or something similar) and put them together. That's it!

It also works fine, when you have to stop your render temporarily - stop and save the image and before you continue, you fill in 180 in the bank-field and start rendering from the other side

Jens

[redstamp]

Thanks for the reply Kranky - currently rendering with 150MB in render buffers to try and improve performance, but doesn't seem to be working anyway.

Jon

[Oshyan]

Changing render buffer size generally isn't going to significantly affect performance. Even very small buffers have minimal effect in most cases. Best to leave it at default unless you have a good reason to change it like this render splitting technique, or using very small buffers for very high resolution renders (the smaller your buffer the more memory is available for other memory-intensive uses).

- Oshyan

[Kranky]

I always set the render buffer size to 2MB, because then the rendered pieces are smaller and I don't have to wait to see the next piece. With a small render buffer size the "hang time" (the time you think terragen is crashed and want to quit the task) is much more lower and the rendering looks more fluent.