Interactive Preview Render (IPR)

CentiLeo supports Interactive Preview Render (IPR) using own custom window which renders the current active document scene, reacts to the changes of camera and materials in real-time. It can also optionally react to changes of geometry objects in real-time if enabled by user.

The purpose of IPR mode is to provide quick render feedback for scene changed made by user during modeling geometry objects, lighting and material tuning.

Here we describe the commands and indicators of IPR:



Move to standard 3ds Max image window

save.png Move the currently rendered IPR image to 3ds Max image window.

AOVs list (extra render images)

AOVs.png Dropdown box containing the list of all AOVs enabled in CentiLeo render settings. All of them are rendered at once and can be switched without re-render.

Pause / Resume render

render_stop.png render_resume.png Pause / Resume render without releasing scene data.

Render region

region2_off.png region2_on.png Enable / Disable Region render. When region render mode is enabled the user can draw a single rectangle area wherein image will continue to render until render settings limits are reached.

Camera update lock

camera_lock_off.png camera_lock_on.png Lock / Unlock real-time camera updates. Yellow color means locked camera.


autofocus_off.png autofocus_on.png Enable / Disable camera autofocus setup. When enabled (green color) the user can choose the screen point with mouse click which is in camera focus. Autofocus picker tunes the focus distance of Depth of Field effect which should be enabled in CentiLeo render settings or in settings of active camera.

Post Processing

settings_off.png settings_on.png Open / Close the right bar with post-processing settings


final_off.png final_on.png Enabled / Disable the “Final Geometry” (Fin Geo) mode. 

By default Fin Geo mode is disabled (white color). In this case the IPR works with the current active document scene considering “Editor” settings of objects. Some of these settings: “Editor” number of subdivisions and motion blur steps in CentiLeo render settings. In this mode IPR renders maximum 4 motion steps for performance reasons regardless of the value in render settings. 

When Fin Geo mode is enabled (green color) the IPR considers the same object and modifier settings that execute for Final/Production mode, e.g. “Renderer” settings of objects (for Subdivision), all motion steps enabled in CentiLeo render settings.

When Fin Geo mode is enabled it is impossible to enable Auto IPR reaction to real-time geometry updates. However, IPR reacts to real-time material/shader and camera changes by user. Basically Fin Geo mode is the same as standard Final mode with some freedom which supports for material and camera changes without need to restart scene prepare stage.

Geometry Auto update 

autoupdate_off.png autoupdate_on.png Enable / Disable Auto IPR reaction to the current scene geometry updates. By default the option is off (white color) because sometimes complex scene tags/expressions may force costly geometry updates on every mouse click.

Geometry Manual update

manual_update.png Manual scene geometry update. This command is needed when Auto update is off, e.g. in case of enabled FIN GEO mode or in cases where enabled Auto update doesn’t detect any geometry change.

Tesselate and Displace

tesselate3.png Manually update tesselation and displacement for all objects with enabled displacement with respect to the current camera position.

This command is only manual because it adaptively evaluates new geometry state for different camera position and is costly for real-time reactions.

Right Bar (Image Setting)

settings_off.png The right bar is enabled by clicking gear icon.

Width/Height determine renger image resolution that is independent from the main render settings (the one enabled for Picture Viewer). 

Locked flag helps to lock the aspect of image size when changing one of the width or height parameters.

Autofit mode fits the width and height of render image to the size of IPR window.

Status Bar

The IPR status bar shows various scene asset counters and general render time and performance (samples per second).

IPR status bar 1.png

GPU Indicators

GPU Indicators can be enabled in IPR right-clicking on the render image and selecting "GPU Info" menu item. These indicators can help with scene and GPU rig inspection. 

There are three kinds of caches involved: GPU Geometry cache, GPU Texture cache (both per GPU) and CPU Texture cache. Each of them has capacity and cache efficiency indicator. If the cache efficiency indicator shows less than 100% (e.g. 80%) then there is out-of-core situation, and 20% of scene data (geometry or textures) are swapped to/from GPU.

IPR status bar 2.png